Rev: 030308

High-Speed Microcontroller User’s Guide













____________________________________________ Maxim Integrated Products 1

---

High-Speed Microcontroller User’s Guide

TABLE OF CONTENTS
1.
INTRODUCTION..............................................................................................................9
2.
ORDERING INFORMATION..........................................................................................10
3.
ARCHITECTURE...........................................................................................................11
3.1
ALU.............................................................................................................................................. 11
3.2
SPECIAL FUNCTION REGISTERS (SFRS).........................................................................................11
3.2.1
Accumulator ......................................................................................................................................... 11
3.2.2
B Register ............................................................................................................................................ 11
3.2.3
Program Status Word........................................................................................................................... 11
3.2.4
Data Pointer(s) ..................................................................................................................................... 11
3.2.5
Stack Pointer........................................................................................................................................ 11
3.2.6
I/O Ports ............................................................................................................................................... 11
3.2.7
Timer/Counters .................................................................................................................................... 12
3.2.8
UARTs.................................................................................................................................................. 12
3.2.9
Scratchpad Registers (RAM) ............................................................................................................... 12
3.2.10 Stack .................................................................................................................................................... 12
3.2.11 Working Registers................................................................................................................................ 12
3.2.12 Program Counter.................................................................................................................................. 12
3.2.13 Address/Data Bus ................................................................................................................................ 12
3.2.14 Watchdog Timer................................................................................................................................... 12
3.2.15 Power Monitor ...................................................................................................................................... 12
3.2.16 Interrupts .............................................................................................................................................. 13
3.2.17 Timing Control...................................................................................................................................... 13
3.2.18 Real-Time Clock................................................................................................................................... 13
3.2.19 Feature Summary ................................................................................................................................ 13
4.
PROGRAMMING MODEL .............................................................................................14
4.1
MEMORY ORGANIZATION ...............................................................................................................14
4.1.1
Memory Map ........................................................................................................................................ 14
4.1.2
Register Map........................................................................................................................................ 14
4.2
SPECIAL FUNCTION REGISTERS .....................................................................................................17
4.2.1
Port 0 (P0)............................................................................................................................................ 25
4.2.2
Stack Pointer (SP)................................................................................................................................ 25
4.2.3
Data Pointer Low 0 (DPL) .................................................................................................................... 26
4.2.4
Data Pointer High 0 (DPH)................................................................................................................... 26
4.2.5
Data Pointer Low 1 (DPL1) .................................................................................................................. 26
4.2.6
Data Pointer High 1 (DPH1)................................................................................................................. 26
4.2.7
Data Pointer Select (DPS) ................................................................................................................... 27
4.2.8
Power Control (PCON)......................................................................................................................... 27
4.2.9
Timer/Counter Control (TCON)............................................................................................................ 28
4.2.10 Timer Mode Control (TMOD) ............................................................................................................... 29
4.2.11 Timer 0 LSB (TL0)................................................................................................................................ 30
4.2.12 Timer 1 LSB (TL1)................................................................................................................................ 30
4.2.13 Timer 0 MSB (TH0) .............................................................................................................................. 30
4.2.14 Timer 1 MSB (TH1) .............................................................................................................................. 30
4.2.15 Clock Control (CKCON) ....................................................................................................................... 31
4.2.16 Port 1 (P1)............................................................................................................................................ 32
4.2.17 External Interrupt Flag (EXIF) .............................................................................................................. 33
4.2.18 RTC Trim Register (TRIM) ................................................................................................................... 34
4.2.19 Serial Port 0 Control (SCON0)............................................................................................................. 35
4.2.20 Serial Data Buffer 0 (SBUF0)............................................................................................................... 36
4.2.21 Port 2 (P2)............................................................................................................................................ 36
4.2.22 Interrupt Enable (IE)............................................................................................................................. 37
4.2.23 Slave Address Register 0 (SADDR0) .................................................................................................. 37
4.2.24 Slave Address Register 1 (SADDR1) .................................................................................................. 38
4.2.25 Port 3 (P3)............................................................................................................................................ 38
Rev: 030308


2 of 175

---

High-Speed Microcontroller User’s Guide

4.2.26 Interrupt Priority (IP)............................................................................................................................. 39
4.2.27 Slave Address Mask Enable Register 0 (SADEN0)............................................................................. 39
4.2.28 Slave Address Mask Enable Register 1 (SADEN1)............................................................................. 40
4.2.29 Serial Port Control (SCON1)................................................................................................................ 40
4.2.30 Serial Data Buffer 1 (SBUF1)............................................................................................................... 41
4.2.31 ROM Size Select (ROMSIZE).............................................................................................................. 42
4.2.32 Power Management Register (PMR) ................................................................................................... 43
4.2.33 Status Register (STATUS) ................................................................................................................... 45
4.2.34 Timed Access Register (TA) ................................................................................................................ 46
4.2.35 Timer 2 Control (T2CON)..................................................................................................................... 46
4.2.36 Timer 2 Mode (T2MOD) ....................................................................................................................... 47
4.2.37 Timer 2 Capture LSB (RCAP2L).......................................................................................................... 48
4.2.38 Timer 2 Capture MSB (RCAP2H) ........................................................................................................ 48
4.2.39 Timer 2 LSB (TL2)................................................................................................................................ 48
4.2.40 Timer 2 MSB (TH2) .............................................................................................................................. 48
4.2.41 Program Status Word (PSW)............................................................................................................... 49
4.2.42 Watchdog Control (WDCON)............................................................................................................... 50
4.2.43 Accumulator (A or ACC) ...................................................................................................................... 51
4.2.44 Extended Interrupt Enable (EIE) .......................................................................................................... 52
4.2.45 B Register (B)....................................................................................................................................... 52
4.2.46 Real-Time Alarm Subsecond Register (RTASS) ................................................................................. 52
4.2.47 Real-Time Alarm Second Register (RTAS) ......................................................................................... 53
4.2.48 Real-Time Alarm Minute Register (RTAM) .......................................................................................... 53
4.2.49 Real-Time Alarm Hour Register (RTAH).............................................................................................. 53
4.2.50 Extended Interrupt Priority (EIP) .......................................................................................................... 54
4.2.51 Real-Time Clock Control Register (RTCC) .......................................................................................... 55
4.2.52 Real-Time Clock Subsecond Register (RTCSS) ................................................................................. 56
4.2.53 Real-Time Clock Second Register (RTCS).......................................................................................... 57
4.2.54 Real-Time Clock Minute Register (RTCM) .......................................................................................... 57
4.2.55 Real-Time Clock Hour Register (RTCH).............................................................................................. 57
4.2.56 Real-Time Clock Day Register 0 (RTCD0) .......................................................................................... 58
4.2.57 Real-Time Clock Day Register 1 (RTCD1) .......................................................................................... 58
4.3
INSTRUCTION TIMING.....................................................................................................................58
4.4
ADDRESSING MODES.....................................................................................................................59
4.4.1
Register Addressing............................................................................................................................. 59
4.4.2
Direct Addressing................................................................................................................................. 60
4.4.3
Register Indirect Addressing................................................................................................................ 60
4.4.4
Immediate Addressing ......................................................................................................................... 61
4.4.5
Register Indirect with Displacement..................................................................................................... 61
4.4.6
Relative Addressing ............................................................................................................................. 61
4.4.7
Page Addressing.................................................................................................................................. 61
4.4.8
Extended Addressing ........................................................................................................................... 62
4.5
PROGRAM STATUS FLAGS .............................................................................................................62
4.5.1
Bit Descriptions .................................................................................................................................... 62
5.
CPU TIMING ..................................................................................................................63
5.1
OSCILLATOR ................................................................................................................................. 63
5.2
XTAL1.......................................................................................................................................... 63
5.3
XTAL2.......................................................................................................................................... 63
5.4
OSCILLATOR CHARACTERISTICS ....................................................................................................63
5.5
CRYSTAL SELECTION.....................................................................................................................63
5.6
INSTRUCTION TIMING.....................................................................................................................64
5.6.1
Single-Cycle Instructions ..................................................................................................................... 65
5.6.2
Two-Cycle Instructions......................................................................................................................... 65
5.6.3
Three-Cycle Instructions ...................................................................................................................... 67
5.6.4
Four-Cycle Instructions ........................................................................................................................ 68
5.6.5
Five-Cycle Instructions......................................................................................................................... 68
5.7
COMPARISON TO THE 8051............................................................................................................71
Rev: 030308


3 of 175

---

High-Speed Microcontroller User’s Guide

6.
MEMORY ACCESS .......................................................................................................76
6.1
INTERNAL PROGRAM MEMORY.......................................................................................................76
6.2
INTERNAL DATA MEMORY ..............................................................................................................76
6.2.1
ROMSIZE Feature ............................................................................................................................... 77
6.3
PROGRAM MEMORY INTERCONNECT ..............................................................................................78
6.4
DATA MEMORY INTERCONNECT .....................................................................................................79
6.5
DATA MEMORY ACCESS ................................................................................................................81
6.5.1
64-Byte Block Move With Dual Data Pointer ....................................................................................... 82
6.5.2
64-Byte Block Move Without Dual Data Pointer .................................................................................. 83
6.6
DATA MEMORY TIMING ..................................................................................................................84
7.
POWER MANAGEMENT ..............................................................................................88
7.1
POWER MANAGEMENT FEATURES..................................................................................................88
7.1.1
Early Warning Power-Fail Interrupt...................................................................................................... 88
7.1.2
Power-Fail Reset.................................................................................................................................. 89
7.1.3
Power-On Reset................................................................................................................................... 89
7.1.4
Bandgap Select.................................................................................................................................... 89
7.1.5
Watchdog Wake-Up ............................................................................................................................. 91
7.1.6
Power Management Summary ............................................................................................................ 91
7.2
POWER CONSERVATION ................................................................................................................93
7.2.1
Idle Mode ............................................................................................................................................. 93
7.2.2
Stop Mode............................................................................................................................................ 93
7.2.3
Ring Oscillator Wake-Up from Stop ..................................................................................................... 94
7.3
POWER MANAGEMENT MODES ......................................................................................................95
7.3.1
Power Management Mode Timing ....................................................................................................... 96
7.3.2
PMM and Peripheral Functions............................................................................................................ 97
7.3.3
Switchback ........................................................................................................................................... 98
7.3.4
Clock Source Selection ........................................................................................................................ 99
7.3.5
Using the Ring Oscillator ................................................................................................................... 100
7.3.6
Switching Between Clock Sources .................................................................................................... 101
8.
RESET CONDITIONS..................................................................................................102
8.1
RESET SOURCES ........................................................................................................................102
8.1.1
Power-On/Fail Reset.......................................................................................................................... 102
8.1.2
Watchdog Timer Reset ...................................................................................................................... 102
8.1.3
External Reset.................................................................................................................................... 103
8.2
RESET STATE..............................................................................................................................103
8.3
NO-BATTERY RESET ...................................................................................................................103
8.4
IN-SYSTEM DISABLE MODE..........................................................................................................104
9.
INTERRUPTS ..............................................................................................................105
9.1
INTERRUPT OVERVIEW ................................................................................................................105
9.2
INTERRUPT SOURCES..................................................................................................................106
9.2.1
External Interrupts.............................................................................................................................. 106
9.2.2
Timer Interrupts.................................................................................................................................. 107
9.2.3
Serial Communication Interrupts........................................................................................................ 107
9.2.4
Real-Time Clock................................................................................................................................. 107
9.2.5
Power-Fail Interrupt............................................................................................................................ 107
9.3
SIMULATED INTERRUPTS .............................................................................................................108
9.4
INTERRUPT PRIORITIES................................................................................................................108
9.5
INTERRUPT ACKNOWLEDGE CYCLE ..............................................................................................108
9.6
INTERRUPT LATENCY...................................................................................................................109
9.7
INTERRUPT REGISTER CONFLICTS ...............................................................................................111
10.
PARALLEL I/O ............................................................................................................112
10.1
PORT 0.................................................................................................................................... 112
10.1.1 General-Purpose I/O .......................................................................................................................... 112
10.1.2 Multiplexed Address/Data Bus AD0–AD7.......................................................................................... 112
Rev: 030308


4 of 175

---

High-Speed Microcontroller User’s Guide

10.2
PORT 2.................................................................................................................................... 113
10.2.1 General-Purpose I/O .......................................................................................................................... 113
10.2.2 Most Significant Address Byte, A8–A15 ............................................................................................ 114
10.3
PORTS 1 AND 3 ........................................................................................................................114
10.4
OUTPUT FUNCTIONS ................................................................................................................115
10.5
CURRENT-LIMITED TRANSITIONS ..............................................................................................115
10.6
INPUT FUNCTIONS ....................................................................................................................115
10.7
READ-MODIFY-WRITE INSTRUCTIONS .......................................................................................116
10.8
INSTRUCTION DESCRIPTION......................................................................................................116
10.9
I/O PORT TIMING .....................................................................................................................116
10.10 OPTIONAL FUNCTIONS..............................................................................................................117
11.
PROGRAMMABLE TIMERS .......................................................................................118
11.1
16-BIT TIMERS.........................................................................................................................118
11.1.1 Timer Mode Control Register (TMOD) Summary .............................................................................. 119
11.1.2 Timer/Counter Control Register (TCON) Summary........................................................................... 120
11.2
MODE 0 ................................................................................................................................... 120
11.3
MODE 1 ................................................................................................................................... 121
11.4
MODE 2 ................................................................................................................................... 122
11.5
MODE 3 ................................................................................................................................... 123
11.6
TIMER 2 ................................................................................................................................... 124
11.6.1 Timer Two Control Register (T2CON) Summary............................................................................... 124
11.6.2 Timer Two Mode Control Register (T2MOD) Summary .................................................................... 125
11.6.3 Timer 2 Capture Registers (RCAP2L, RCAP2H) Summary .............................................................. 125
11.7
TIMER 2 MODES.......................................................................................................................126
11.7.1 16-Bit Timer/Counter.......................................................................................................................... 126
11.7.2 16-Bit Timer with Capture .................................................................................................................. 126
11.7.3 16-Bit Auto-Reload Timer/Counter..................................................................................................... 127
11.7.4 Up/Down Count Auto-Reload Timer/Counter .................................................................................... 129
11.7.5 Baud-Rate Generator......................................................................................................................... 129
11.7.6 Timer Output Clock Generator........................................................................................................... 130
11.8
TIME BASE SELECTION.............................................................................................................131
11.9
WATCHDOG TIMER...................................................................................................................132
11.9.1 Watchdog Control Register (WDCON) Summary.............................................................................. 134
11.9.2 Clock Control Register (CKCON) Summary ...................................................................................... 135
12.
SERIAL I/O ..................................................................................................................136
12.1
SERIAL MODE SUMMARY ..........................................................................................................136
12.1.1 Mode 0 ............................................................................................................................................... 136
12.1.2 Mode 1 ............................................................................................................................................... 136
12.1.3 Mode 2 ............................................................................................................................................... 137
12.1.4 Mode 3 ............................................................................................................................................... 137
12.2
SERIAL PORT INITIALIZATION ....................................................................................................137
12.2.1 Serial Port Control 0 Register (SCON0; 98h) .................................................................................... 138
12.2.2 Serial Port Control 1 Register (SCON1; C0h).................................................................................... 139
12.2.3 Power Control Register (PCON; 87h) ................................................................................................ 140
12.2.4 Watchdog Control Register (WDCON; D8h)...................................................................................... 140
12.2.5 Timer Two Control Register ( T2CON; C8h)...................................................................................... 140
12.3
BAUD RATES............................................................................................................................140
12.3.1 Mode 0 ............................................................................................................................................... 140
12.3.2 Mode 2 ............................................................................................................................................... 141
12.3.3 Mode 1 or 3 ........................................................................................................................................ 141
12.4
SERIAL I/O DESCRIPTION .........................................................................................................143
12.4.1 Mode 0 ............................................................................................................................................... 143
12.4.2 Mode 1 ............................................................................................................................................... 145
12.4.3 Mode 2 ............................................................................................................................................... 147
12.4.4 Mode 3 ............................................................................................................................................... 149
Rev: 030308


5 of 175

---

High-Speed Microcontroller User’s Guide

12.5
FRAMING ERROR DETECTION ...................................................................................................149
12.6
MULTIPROCESSOR COMMUNICATION ........................................................................................151
13.
TIMED-ACCESS PROTECTION .................................................................................153
13.1
PROTECTED BITS .....................................................................................................................153
13.2
PROTECTION SCHEME..............................................................................................................153
13.3
TIMED-ACCESS PROTECTS WATCHDOG....................................................................................154
14.
REAL-TIME CLOCK....................................................................................................156
14.1
STARTING AND STOPPING THE RTC..........................................................................................157
14.2
SETTING AND READING THE RTC TIME REGISTERS...................................................................157
14.3
USING THE RTC ALARM ...........................................................................................................158
14.4
USING THE DAY OF THE WEEK BITS ..........................................................................................159
14.5
CHOOSING AN RTC CRYSTAL...................................................................................................159
14.6
CALIBRATING THE RTC OSCILLATOR ........................................................................................160
15.
BATTERY BACKUP....................................................................................................161
15.1
SELECTING A BATTERY.............................................................................................................161
15.2
LITHIUM BATTERY CONSIDERATIONS.........................................................................................162
16.
INSTRUCTION SET DETAILS ....................................................................................163
17.
TROUBLESHOOTING.................................................................................................171
17.1
DEVICE OPERATES AT ONE-THIRD THE CRYSTAL SPEED ...........................................................171
17.2
DEVICE RESETS FOR NO REASON ............................................................................................171
17.3
ACCESS TO INTERNAL MOVX SRAM IS UNSUCCESSFUL ..........................................................171
17.4
REAL-TIME CLOCK DOES NOT OPERATE OR KEEP ACCURATE TIME........................................... 171
17.5
SERIAL PORT DOES NOT WORK ...............................................................................................172
17.6
HIGH-SPEED MICROCONTROLLER DOES NOT WORK IN EXISTING 8051 DESIGN......................... 172
18.
MICROCONTROLLER DEVELOPMENT SUPPORT..................................................173
18.1
TECHNICAL SUPPORT...............................................................................................................173
18.2
DEVELOPMENT TOOLS .............................................................................................................173
18.3
SOFTWARE COMPATIBILITY ......................................................................................................173
18.4
HIGH-LEVEL LANGUAGE COMPILERS.........................................................................................173
19.
REVISION HISTORY ...................................................................................................175

Rev: 030308


6 of 175

---

High-Speed Microcontroller User’s Guide

LIST OF FIGURES
Figure 4-1. Memory Map .......................................................................................................................... 15
Figure 4-2. Register Map .......................................................................................................................... 16
Figure 4-3. Scratchpad Register Addressing............................................................................................ 16
Figure 5-1. Crystal Connection ................................................................................................................. 64
Figure 5-2. Clock Source Input ................................................................................................................. 64
Figure 5-3. Single-Cycle Instruction Timing.............................................................................................. 66
Figure 5-4. Two-Cycle Instruction Timing ................................................................................................. 67
Figure 5-5. Three-Cycle Instruction Timing .............................................................................................. 69
Figure 5-6. Four-Cycle Instruction Timing ................................................................................................ 70
Figure 5-7. Five-Cycle Instruction Timing ................................................................................................. 71
Figure 6-1. Program Memory Interface .................................................................................................... 80
Figure 6-2. Program Memory Signals....................................................................................................... 80
Figure 6-3. Data Memory Interface........................................................................................................... 81
Figure 6-4. Full-Speed MOVX Instruction................................................................................................. 85
Figure 6-5. Three-Cycle MOVX Instruction............................................................................................... 86
Figure 6-6. Four-Cycle MOVX Instruction................................................................................................. 87
Figure 7-1. Power Cycle Operation .......................................................................................................... 90
Figure 7-2. Internal Timing Relationships in PMM1.................................................................................. 97
Figure 9-1. Interrupt Functional Description ........................................................................................... 110
Figure 10-1. Port 0 Functional Circuitry .................................................................................................. 113
Figure 10-2. Port 2 Functional Circuitry .................................................................................................. 114
Figure 10-3. I/O Port Timing for MOV Instruction ................................................................................... 117
Figure 11-1. Timer/Counter 0 and 1, Modes 0 and 1 .............................................................................121
Figure 11-2. Timer/Counter 0 and 1, Mode 2 ......................................................................................... 122
Figure 11-3. Timer/Counter 0 Mode 3 .................................................................................................... 123
Figure 11-4. Timer/Counter 2 with Optional Capture.............................................................................. 126
Figure 11-5. Timer/Counter 2 Auto-Reload Mode ..................................................................................128
Figure 11-6. Timer/Counter 2, Baud-Rate Generator Mode ...................................................................130
Figure 11-7. Timer/Counter 2, Clock-Out Mode ..................................................................................... 131
Figure 11-8. Watchdog Timer ................................................................................................................. 132
Figure 12-1. Serial Port Mode 0 ............................................................................................................. 144
Figure 12-2. Serial Port Mode 1 ............................................................................................................. 146
Figure 12-3. Serial Port Mode 2 ............................................................................................................. 148
Figure 12-4. Serial Port Mode 3 ............................................................................................................. 150
Figure 13-1. Timed-Access Examples.................................................................................................... 154

Rev: 030308


7 of 175

---

High-Speed Microcontroller User’s Guide

LIST OF TABLES
Table 4-A. DS80C310 SFR Locations ...................................................................................................... 17
Table 4-B. DS80C310 SFR Reset Values ................................................................................................ 18
Table 4-C. DS80C320/DS80C323 SFR Locations ...................................................................................19
Table 4-D. DS80C320/DS80C323 SFR Reset Values ............................................................................. 20
Table 4-E. DS83C520/DS87C520 SFR Locations ...................................................................................21
Table 4-F. DS83C520/DS87C520 SFR Reset Values ............................................................................. 22
Table 4-G. DS87C530 SFR Locations ..................................................................................................... 23
Table 4-H. DS87C530 SFR Reset Values................................................................................................ 24
Table 4-I. Instructions That Affect Flag Settings....................................................................................... 62
Table 5-A. Instruction Timing Comparison ............................................................................................... 72
Table 5-B. Instruction Speed Summary.................................................................................................... 75
Table 6-A. Data Memory Access Control ................................................................................................. 77
Table 6-B. ROMSIZE Register Settings ................................................................................................... 78
Table 6-C. Data Memory Cycle Stretch Values ........................................................................................ 85
Table 7-A. Pin States in Power-Saving Modes......................................................................................... 94
Table 7-B. Crystal vs. MIPS Comparison ................................................................................................. 95
Table 7-C. Power Management and Status Bit Summary ........................................................................ 96
Table 7-D. Effect of Clock Modes on Timer Operation ............................................................................. 98
Table 7-E. Clock Control and Status Bit Summary................................................................................. 100
Table 8-A. No-Battery Reset Default ...................................................................................................... 104
Table 9-A. Interrupt Summary ................................................................................................................ 105
Table 12-A. Serial I/O Modes ................................................................................................................. 137
Table 14-A. Real-Time Clock Control and Status Bit Summary .............................................................156
Table 15-A. Suggested Batteries for the DS87C530 ..............................................................................161
Table 15-B. Battery-Backed SFRs ......................................................................................................... 162
Table 18-A. Product Feature Matrix ....................................................................................................... 174

Rev: 030308


8 of 175

---

High-Speed Microcontroller User’s Guide

1. INTRODUCTION
Maxim high-speed microcontrollers are 8051-compatible devices that provide improved performance and
power consumption compared to the original version. They retain instruction-set and object-code
compatibility with the 8051, yet perform the same operations in fewer clock cycles. Consequently, more
throughput is possible for the same crystal speed. As an alternative, the high-speed microcontroller’s
more efficient design allows a much slower crystal speed to get the same results as an original 8051,
using much less power.

The fundamental innovation of the high-speed microcontroller is the use of only four clocks per
instruction cycle compared with 12 for the original 8051. This results in up to three times improvement in
performance. In addition, the high-speed microcontroller is updated with several new peripherals and
features while providing all of the standard features of an 80C32. These include 256 bytes of on-chip
RAM for variables and stack, 32 I/O ports, three 16-bit timer/counters, and an on-chip UART.

In addition to improved efficiency, most devices can operate at a maximum clock rate of 33MHz or
40MHz. Combined with the three times performance, this allows for a maximum performance equivalent
to a 99MHz or 120MHz 8051. This level of computing power is comparable to many 16-bit processors,
but without the added expense.

A number of peripherals were added to the original 80C32 core. Some devices have a programmable
watchdog timer to supervise the system. It counts up to a user programmable interval and then reset the
CPU unless cleared by software. Other features such as a second, full-function UART and dual data
pointers are available to minimize external interrupts allows greater flexibility in dealing with external
events.

Some devices incorporate power management modes that allow the device to dynamically vary the
internal clock speed from 4 clocks per cycle (default) to 64 or 1024 clocks per cycle. Because power
consumption is directly proportional to clock speed, the device can reduce its operating frequency during
periods of little or no activity. This greatly reduces power consumption. The switchback feature allows
the device to quickly return in divide-by-4 mode upon receipt of an interrupt or serial port activity,
allowing the device to respond to external events while in power management mode.

Various memory configurations are available with the high-speed microcontroller family. EPROM and
Mask programmable ROM versions are available for program memory. Some versions incorporate
extended MOVX SRAM on-chip, reducing or eliminating the need for external data memory. This
memory can be made nonvolatile in the DS87C530 through the use of an external lithium battery.

Note: Information contained in specific data sheets supersedes general information found in this user’s
guide. Designers are cautioned to obtain and read carefully the data sheets, this user’s guide, and any
relevant supplements before using any Maxim microcontroller.

Rev: 030308


9 of 175

---

High-Speed Microcontroller User’s Guide

2. ORDERING
INFORMATION
The high-speed microcontroller family follows the part numbering convention shown below. Note that all
combinations of devices are not currently available. Refer to the individual data sheets for the available
versions.

DS80C320-MCG
SPEED: D 18MHz

G
25MHz

L
33MHz

R
40MHz

TEMPERATURE:
C 0°C to +70°C

N
-40°C to +85°C

PACKAGE:
M PLASTIC

Q
PLCC


E THIN PLASTIC QUAD FLAT PACK (TQFP)


F PLASTIC QUAD FLAT PACK (QFP)

W
WINDOWED
CERDIP

K
WINDOWED
CERQUAD

OPERATING VOLTAGE:
0
+5V


3
+3V OR WIDE VOLTAGE

MEMORY TYPE:
0
ROMless

3
ROM
7 EPROM

Rev: 030308


10 of 175

---

Document Outline

• TABLE OF CONTENTS
• LIST OF FIGURES
• LIST OF TABLES
• ÿ
• • ÿ
  • • ÿ
    • ÿ
    • ÿ
    • ÿ
    • ÿ
    • ÿ
    • ÿ
    • ÿ
    • ÿ
    • ÿ
• • ÿ
    • ÿ
      • ÿ
  • Special Function Registers
    • Port 0 (P0)
    • Stack Pointer (SP)
    • Data Pointer Low 0 (DPL)
    • Data Pointer High 0 (DPH)
    • Data Pointer Low 1 (DPL1)
    • Data Pointer High 1 (DPH1)
    • Data Pointer Select (DPS)
    • Power Control (PCON)
    • Timer/Counter Control (TCON)
    • Timer Mode Control (TMOD)
    • Timer 0 LSB (TL0)
    • Timer 1 LSB (TL1)
    • Timer 0 MSB (TH0)
    • Timer 1 MSB (TH1)
    • Clock Control (CKCON)
    • Port 1 (P1)
    • External Interrupt Flag (EXIF)
    • RTC Trim Register (TRIM)
    • Serial Port 0 Control (SCON0)
    • Serial Data Buffer 0 (SBUF0)
    • Port 2 (P2)
    • Interrupt Enable (IE)
    • ÿ
    • ÿ
    • Interrupt Priority (IP)
    • Slave Address Mask Enable Register 0 (SADEN0)
    • Slave Address Mask Enable Register 1 (SADEN1)
    • ÿ
    • ROM Size Select (ROMSIZE)
    • Power Management Register (PMR)
    • Status Register (STATUS)
    • Timed Access Register (TA)
    • Timer 2 Control (T2CON)
    • Timer 2 Mode (T2MOD)
    • Timer 2 Capture LSB (RCAP2L)
    • Timer 2 Capture MSB (RCAP2H)
    • Timer 2 LSB (TL2)
    • Timer 2 MSB (TH2)
    • Program Status Word (PSW)
    • ÿ
    • Accumulator (A or ACC)
    • Extended Interrupt Enable (EIE)
    • ÿ
    • Real-Time Alarm Minute Register (RTAM)
    • Real-Time Alarm Hour Register (RTAH)
    • Extended Interrupt Priority (EIP)
    • Real-Time Clock Control Register (RTCC)
    • ÿ
    • Real-Time Clock Second Register (RTCS)
    • Real-Time Clock Minute Register (RTCM)
    • ÿ
    • Real-Time Clock Day Register 1 (RTCD1)
  • ÿ
    • ÿ
    • ÿ
    • ÿ
    • Extended Addressing
  • ÿ
• ÿ
  • ÿ
  • ÿ
  • Instruction Timing
    • ÿ
    • Three-Cycle Instructions
    • ÿ
  • Comparison to the 8051
• ÿ
  • ÿ
  • ÿ
  • Data Memory Access
    • ÿ
  • Data Memory Timing
• ÿ
  • • ÿ
    • Power-Fail Reset
    • ÿ
    • Watchdog Wake-Up
  • ÿ
    • ÿ
    • ÿ
  • ÿ
    • ÿ
    • ÿ
    • Switching Between Clock Sources
• ÿ
  • • ÿ
    • External Reset
  • ÿ
  • ÿ
• • ÿ
  • • ÿ
    • Timer Interrupts
    • ÿ
  • Simulated Interrupts
  • ÿ
  • ÿ
  • Interrupt Register Conflicts
• • ÿ
    • ÿ
  • Port 2
    • ÿ
  • ÿ
  • ÿ
  • ÿ
  • Optional Functions
• ÿ
  • • ÿ
    • Timer/Counter Control Register (TCON) Summary
  • Mode 1
  • Mode 2
  • Mode 3
  • Timer 2
    • ÿ
    • Timer Two Mode Control Register (T2MOD) Summary
    • • Least Significant Byte Capture of Timer 2 (RCAP2L)
      • Most Significant Byte Capture of Timer 2 (RCAP2H)
  • ÿ
    • ÿ
    • Up/Down Count Auto-Reload Timer/Counter
    • ÿ
    • Timer Output Clock Generator
  • Time Base Selection
  • Watchdog Timer
    • ÿ
• • ÿ
    • ÿ
    • ÿ
  • • ÿ
    • Power Control Register (PCON; 87h)
    • ÿ
  • ÿ
    • ÿ
  • Serial I/O Description
    • ÿ
    • ÿ
  • ÿ
  • Multiprocessor Communication
• • ÿ
  • ÿ
• • Starting and Stopping the RTC
  • ÿ
  • ÿ
  • ÿ
• 15. BATTERY BACKUP
  • ÿ
• ÿ
  • ÿ
  • ÿ
  • Serial Port Does Not Work
• ÿ
  • ÿ
  • ÿ

---