71M6541D Datasheet, PDF (61/166 Pages) Maxim Integrated Products – 0.1% Accuracy Over 2000:1 Current Range Energy Meter ICs

71M6541D/F/G and 71M6542F/G Data Sheet
2.5.8.2 Digital I/O for the 71M6541D/F/G
A total of 32 combined SEG/DIO pins plus 5 SEG outputs are available for the 71M6541D/F/G. These
pins can be categorized as follows:
17 combined SEG/DIO segment pins:
o SEGDIO4…SEGDIO5 (2 pins)
o SEGDIO9…SEGDIO14 (6 pins)
o SEGDIO19…SEGDIO25 (7 pins)
o SEGDIO44…SEGDIO45 (2 pins)
15 combined SEG/DIO segment pins shared with other functions:
o SEGDIO0/WPULSE, SEGDIO1/VPULSE (2 pins)
o SEGDIO2/SDCK, SEGDIO3/SDATA (2 pins)
o SEGDIO6/XPULSE, SEGDIO7/YPULSE (2 pins)
o SEGDIO8/DI (1 pin)
o SEGDIO26/COM5, SEGDIO27/COM4 (2 pins)
o SEGDIO36/SPI_CSZ…SEGDIO39/SPI_CKI (4 pins)
o SEGDIO51/OPT_TX, SEGDIO55/OPT_RX (2 pins)
5 dedicated SEG segment pins are available:
o ICE Inteface pins: SEG48/E_RXTX, SEG49/E_TCLK, SEG50/E_RST (3 pins)
o Test Port pins: SEG46/TMUX2OUT, SEG47/TMUXOUT (2 pins)
There are four dedicated common segment outputs (COM0…COM3) plus the two additional shared common
segment outputs that are listed under combined SEG/DIO shared pins (SEGDIO26/COM5,
SEGDIO27/COM4).
Thus, in a configuration where none of these pins are used as DIOs, there can be up to 37 LCD segment
pins with 4 commons, or 35 LCD segment pins with 6 commons. And in a configuration where LCD
segment pins are not used, there can be up to 32 DIO pins.
The configuration for pins SEGDIO19 to SEGDIO27 is shown in Table 49, and the configuration for pins
SEGDIO36-39 and SEGDIO44-45 is shown in Table 50. SEG46 to SEG50 cannot be configured for DIO.
The configuration for pins SEGDIO51 and SEGDIO55 is shown in Table 51.
Table 48: Data/Direction Registers for SEGDIO0 to SEGDIO14 (71M6541D/F/G)
SEGDIO
Pin #
Configuration:
0 = DIO, 1 = LCD
SEG Data Register
DIO Data Register
Direction Register:
0 = input, 1 = output
Internal Resources
Configurable
(see Table 47)
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 –
0 123 4 56 7 01 2 3456–
LCD_MAP[7:0] (I/O RAM 0x240B)
LCD_MAP[14:8] (I/O RAM 0x240A)
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 –
LCD_SEG0[5:0] to LCD_SEG14[5:0] (I/O RAM 0x2410[5:0] to 0x241E[5:0]
0 123
P0 (SFR 0x80)
4 567
P0 (SFR 0x80)
0 12 3
P1 (SFR 0x90)
4 56 7
P1 (SFR 0x90)
01 2 3
P2 (SFR 0xA0)
45 6 7
P2 (SFR 0xA0)
012–
P3 (SFR 0xB0)
456–
P3 (SFR 0xB0)
– –YY Y YY YYY Y Y– – – –