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-12.png)
Data Sheet 71M6531D/F-71M6532D/F FDS 6531/6532 005
12 Rev 2
The duration of each multiplexer state depends on the number of ADC samples processed by the FIR,
which is set by FIR_LEN[1:0]. Each multiplexer state will start on the rising edge of CK32. The MUX_CTRL
signal sends an FIR_START command to begin the calculation of a sample value from the ADC bit
stream by the FIR. Upon receipt of the FIR_DONE signal from the FIR, the multiplexer will wait until the
next CK32 rising edge to increment its state and initiate the next FIR conversion. FIR conversions require
1, 2, or 3 CK32 cycles. The number of CK32 cycles is determined by FIR_LEN[1:0], as shown in Table 2.
1.2.3 A/D Converter (ADC)
A single delta-sigma A/D converter digitizes the voltage and current inputs to the 71M6531D/F and
71M6532D/F. The resolution of the ADC is programmable using the I/O RAM M40MHZ and M26MHZ bits
(see Table 2). The CE code must be tailored for use with the selected ADC resolution.
Table 2: ADC Resolution
Setting for
[M40MHZ, M26MHZ]
FIR_LEN[1:0]
CK32
Cycles
FIR CE Cycles Resolution
[00], [10] or [11]
0
1
2
1
2
3
138
288
384
18 bits
21 bits
22 bits
[01]
0
1
2
1
2
3
186
384
588
19 bits
22 bits
24 bits
Initiation of each ADC conversion is controlled by MUX_CTRL as described above. At the end of each
ADC conversion, the FIR filter output data is stored into the CE RAM location determined by the MUX
selection.
1.2.4 FIR Filter
The finite impulse response filter is an integral part of the ADC and it is optimized for use with the multiplexer.
The purpose of the FIR filter is to decimate the ADC output to the desired resolution. At the end of each
ADC conversion, the output data is stored into the fixed CE RAM location determined by the multiplexer
selection as shown in Table 3. FIR data is stored LSB justified, but shifted left by eight bits.
Table 3: ADC RAM Locations
Address (HEX)
Name
Address (HEX)
Name
0x00
IA
0x09
AUX
0x01
VB
0x0A
TEMP
0x02
IB
0x0B
VBAT
0x03
VA
1.2.5 Voltage References
The device includes an on-chip precision bandgap voltage reference that incorporates auto-zero techniques.
The reference is trimmed to minimize errors caused by component mismatch and drift. The result is a
voltage output with a predictable temperature coefficient.
The amplifier within the reference is chopper stabilized, i.e. the polarity can be switched by the MPU using
CHOP_E[1:0] (IORAM 0x2002[5:4]). The CHOP_E[1:0] field enables the MPU to operate the chopper circuit
in regular or inverted operation, or in toggling mode. When the chopper circuit is toggled in between
multiplexer cycles, DC offsets on the measured signals will automatically be averaged out.
The general topology of a chopped amplifier is shown in Figure 3.