M38203M4 Datasheet, PDF (308/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPENDIX
3.3 Control registers
Watchdog timer control register
b7 b6 b5 b4 b3 b2 b1 b0
Watchdog timer control register (WDTCON) [Address 3716]
B
Name
0 ^{Watchdog timer H}
to ^bits
5
Functions
At reading, the count value of
watchdog timer H is read.
6 Nothing is allocated. This bit cannot be written to and
is fixed to “1” at reading.
At reset R W
1
×
(Note)
1 1×
7 ^{Watchdog timer H} _{0: Underflow from watchdog}
0
count source
timer L
selection bit
(WDT is used as 14-bit timer)
1: f(XIN)/16 or f(XCIN)/16
(WDT is used as 6-bit timer)
Note: When a value is written to address 3716, the following values are set,
so that the watchdog timer starts a count operation.
Watchdog timer H = “3F16”
Watchdog timer L = “FF16”
Fig. 3.3.13 Structure of watchdog timer control register
Segment output enable register
b7 b6 b5 b4 b3 b2 b1 b0
00
Segment output enable register (SEG) [Address 3816]
B
Name
Functions
At reset R W
0 Segment output ^{0: Input ports P3}0–P37
0
enable bit 0
1: Segment output SEG16–SEG23
1 ^{Segment output} 0: I/O ports P00, P01
0
enable bit 1
1: Segment output SEG24, SEG25
2 Segment output 0: I/O ports P02–P07
0
enable bit 2
1: Segment output SEG26–SEG31
3 Segment output ^{0: I/O ports P10, P11}
0
enable bit 3
1: Segment output SEG32, SEG33
4 Segment output 0: I/O port P12
0
enable bit 4
1: Segment output SEG34
5 ^{Segment output 0: I/O ports P13–P17}
0
enable bit 5
1: Segment output SEG35–SEG39
6,7 Fix these bits to “0.”
0 00
Fig. 3.3.14 Structure of segment output register
3–24
3820 GROUP USER’S MANUAL