Datasheet
Table Of Contents
- 1 Hardware Description
- 1.1 Hardware Overview
- 1.2 Analog Front End (AFE)
- 1.3 Digital Computation Engine (CE)
- 1.4 80515 MPU Core
- 1.4.1 Memory Organization and Addressing
- 1.4.2 Special Function Registers (SFRs)
- 1.4.3 Generic 80515 Special Function Registers
- 1.4.4 Special Function Registers (SFRs) Specific to the 71M6531D/F and 71M6532D/F
- 1.4.5 Instruction Set
- 1.4.6 UARTs
- 1.4.7 Timers and Counters
- 1.4.8 WD Timer (Software Watchdog Timer)
- 1.4.9 Interrupts
- 1.5 On-Chip Resources
- 1.5.1 Oscillator
- 1.5.2 Internal Clocks
- 1.5.3 Real-Time Clock (RTC)
- 1.5.4 Temperature Sensor
- 1.5.5 Physical Memory
- 1.5.6 Optical Interface
- 1.5.7 Digital I/O – 71M6531D/F
- 1.5.8 Digital I/O – 71M6532D/F
- 1.5.9 Digital IO – Common Characteristics for 71M6531D/F and 71M6532D/F
- 1.5.10 LCD Drivers – 71M6531D/F
- 1.5.11 LCD Drivers – 71M6532D/F
- 1.5.12 LCD Drivers – Common Characteristics for 71M6531D/F and 71M6532D/F
- 1.5.13 Battery Monitor
- 1.5.14 EEPROM Interface
- 1.5.15 SPI Slave Port
- 1.5.16 Hardware Watchdog Timer
- 1.5.17 Test Ports (TMUXOUT pin)
- 2 Functional Description
- 3 Application Information
- 3.1 Connection of Sensors
- 3.2 Connecting 5-V Devices
- 3.3 Temperature Measurement
- 3.4 Temperature Compensation
- 3.5 Connecting LCDs
- 3.6 Connecting I2C EEPROMs
- 3.7 Connecting Three-Wire EEPROMs
- 3.8 UART0 (TX/RX)
- 3.9 Optical Interface (UART1)
- 3.10 Connecting the V1 Pin
- 3.11 Connecting the Reset Pin
- 3.12 Connecting the Emulator Port Pins
- 3.13 Connecting a Battery
- 3.14 Flash Programming
- 3.15 MPU Firmware
- 3.16 Crystal Oscillator
- 3.17 Meter Calibration
- 4 Firmware Interface
- 4.1 I/O RAM and SFR Map – Functional Order
- 4.2 I/O RAM Description – Alphabetical Order
- 4.3 CE Interface Description
- 5 Electrical Specifications
- 5.1 Absolute Maximum Ratings
- 5.2 Recommended External Components
- 5.3 Recommended Operating Conditions
- 5.4 Performance Specifications
- 5.4.1 Input Logic Levels
- 5.4.2 Output Logic Levels
- 5.4.3 Power-Fault Comparator
- 5.4.4 Battery Monitor
- 5.4.5 Supply Current
- 5.4.6 V3P3D Switch
- 5.4.7 2.5 V Voltage Regulator
- 5.4.8 Low-Power Voltage Regulator
- 5.4.9 Crystal Oscillator
- 5.4.10 LCD DAC
- 5.4.11 LCD Drivers
- 5.4.12 Optical Interface
- 5.4.13 Temperature Sensor
- 5.4.14 VREF
- 5.4.15 ADC Converter, V3P3A Referenced
- 5.5 Timing Specifications
- 5.6 Typical Performance Data
- 5.7 71M6531D/F Package
- 5.8 71M6532D/F Package
- 5.9 Pin Descriptions
- 6 Ordering Information
- 7 Related Information
- 8 Contact Information
- Appendix A: Acronyms
- Appendix B: Revision History
![](/manual/maxim-integrated/71m6531f-im-f/datasheet-english/images/img-67.png)
FDS 6531/6532 005 Data Sheet 71M6531D/F-71M6532D/F
Rev 2 67
3.7 Connecting Three-Wire EEPROMs
µWire EEPROMs and other compatible devices should be connected to the DIO pins DIO4 and DIO5, as
shown in Figure 34 and described below:
• DIO5 connects to both the DI and DO pins of the three-wire device.
• The CS pin must be connected to a vacant DIO pin of the 71M6531.
• In order to prevent bus contention, a 10 kΩ to resistor is used to separate the DI and DO signals.
• The CS and CLK pins should be pulled down with resistors to prevent operation of the three-wire device
on power-up, before the 71M6531 can establish a stable signal for CS and CLK.
• The DIO_EEX[1:0] register in I/O RAM must be set to 2 (b10) in order to convert the DIO pins DIO4
and DIO5 to µWire pins.
The µ-Wire EEPROM interface is only functional when MPU_DIV[2:0] = 000.
Figure 34: Three-Wire EEPROM Connection
3.8 UART0 (TX/RX)
The UART0 RX pin should be pulled down by a 10 kΩ resistor and additionally protected by a 100 pF
ceramic capacitor, as shown in Figure 35.
Figure 35: Connections for UART0
3.9 Optical Interface (UART1)
The OPT_TX and OPT_RX pins can be used for a regular serial interface (by connecting a RS-232
transceiver for example), or they can be used to directly operate optical components (for example, an
infrared diode and phototransistor implementing a FLAG interface). Figure 36 shows the basic connections
for UART1. The OPT_TX pin becomes active when the I/O RAM register OPT_TXE is set to 00.
TX
RX
71M6531D/F, 71M6532D/F
10 k
Ω
100 pF
RX
TX
71M653X
EEPROM
100 kΩ
DIO4
DIO5
CLK
DI
V3P3D
100 kΩ
CS
DIOn
DO
10 k
Ω
VCC