APPLICATION
2.7 LCD drive control circuit
3822 GROUP USER’S MANUAL
2–166
0
1
Table 2.7.2 Pin functions by setting the corresponding registers when they are not used as seg-
ment output pins
Ports
Pins
(1) Segment output pins (SEG0–SEG31)
Up to 32 segment outputs can be selected. Table 2.7.3 shows setting of segment output pins for LCD
display.
Table 2.7.3 Setting of segment output pins for LCD display
PULLA (Address 001616) b3
(Bit 3 of PULL register A)
1
0
1
0
P1D (Address 000316) b0
(Bit 0 of port P1 direction register)
P0D (Address 000116) b0
(Bit 0 of port P0 direction register)
PULLA (Address 001616) b0
(Bit 0 of PULL register A)
PULLA (Address 001616) b1
(Bit 1 of PULL register A)
Setting
Register
Value
Pin function
No pull-down
Output port
No pull-down
Input port
Output port
Input port
Pull-down pin
SEG0–SEG11
Segment output-only pin
P00–P07
P10–P17
P34–P37
Setting
0
1
0
Input port
1
Pull-down pin
(Valid when bit 0 of port P0 direction
register is “0”)
Pull-down pin
(Valid when bit 0 of port P1 direction
register is “0”)
Ports P34–P37 are used as segment signal output pins (SEG12–SEG15) by setting
bit 0 of the segment output enable register (address 003816) to “1.”
Ports P00 and P01 are used as segment signal output pins (SEG16, SEG17) by setting
bit 1 of the segment output enable register (address 003816) to “1.”
Ports P02–P07 are used as segment signal output pins (SEG18–SEG23) by setting
bit 2 of the segment output enable register (address 003816) to “1.”
Ports P10 and P11 are used as segment signal output pins (SEG24, SEG25) by setting
bit 3 of the segment output enable register (address 003816) to “1.”
P12/SEG26
Ports P12 is used as segment signal output pins (SEG26) by setting bit 4 of the
segment output enable register (address 003816) to “1.”
Ports P13–P17 are used as segment signal output pins (SEG27–SEG31) by setting
bit 5 of the segment output enable register (address 003816) to “1.”
P34/SEG12–
P37/SEG15
P00/SEG16,
P01/SEG17
P02/SEG18–
P07/SEG23
P10/SEG24,
P11/SEG25
P13/SEG27–
P17/SEG31