UPD75238GJ NEC [NEC], UPD75238GJ Datasheet - Page 123

• Manufacturer Part Number: UPD75238GJ
• Description: 4 BIT SINGLE-CHIP MICROCOMPUTER
• Manufacturer: NEC [NEC]

Address
F8AH
Address
F88H
(4) Display mode register (DSPM)
(5) Digit select register (DIGS)
The display mode register (DSPM) is a 4-bit register for enable/disable setting for the display operation
and for specifying the number of display segments. Fig. 4-70 shows the format of the register.
The display mode register is set with a 4-bit memory manipulation instruction.
Before a standby mode (STOP mode or HALT mode) can be set or the subsystem clock (f
for operation, display must be disabled by setting DSPM.3 to 0.
A RESET input clears all bits to 0.
The digit select register (DIGS) is a 4-bit register that specifies the number of display digits. Fig. 4-71 shows
the format of the register.
DIGS is set with a 4-bit memory manipulation instruction. This register enables the number of display
digits to be selected from 9 to 16 digits. No other values can be selected.
A RESET input initializes the register to 1000B so that 9-digit display is selected.
DSPM3
DIGS3
3
3
DSPM2
DIGS2
2
2
Bit for specifying the number of display segments
Remark Segments in parentheses are added when pins S16 to S23 are specified as dynamic mode
Display operation enable/disable bit
DSPM1
DSPM2
DSPM3
DIGS1
1
1
0
0
0
0
1
1
1
1
Fig. 4-70 Display Mode Register Format
in STATB.
DSPM0
DSPM1
Fig. 4-71 Digit Select Register Format
DIGS0
0
0
0
0
1
1
0
0
1
1
0
1
Caution Do not set a value from 0 to 7 for N.
DSPM0
Display disabled
Display enabled
Symbol
DIGS
Symbol
DSPM
0
1
0
1
0
1
0
1
DIGS0-3 set value
Number of display segments
9 segments (+ 8 segments)
10 segments (+ 8 segments)
11 segments (+ 8 segments)
12 segments (+ 8 segments)
13 segments (+ 8 segments)
14 segments (+ 8 segments)
15 segments (+ 8 segments)
16 segments (+ 8 segments)
N (= 8 to 15)
Number of display digits
N + 1
XT
PD75238
) can be used
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