HD64F3028F25 Datasheet, PDF (471/925 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

12.1.4 Register Configuration
Table 12.2 summarizes the WDT registers.
Table 12.2 WDT Registers
Address^*1
Write^*2 Read
Name
Abbreviation
H'FFF8C H'FFF8C Timer control/status register TCSR
H'FFF8D Timer counter
TCNT
H'FFF8E H'FFF8F Reset control/status register RSTCSR
Notes: 1. Lower 20 bits of the address in advanced mode.
2. Write word data starting at this address.
3. Only 0 can be written in bit 7, to clear the flag.
R/W
R/(W)^*3
R/W
R/(W)^*3
Initial Value
H'18
H'00
H'3F
12.2 Register Descriptions
12.2.1 Timer Counter (TCNT)
TCNT is an 8-bit readable and writable up-counter.
Bit
7
6
5
4
3
2
1
0
Initial value
Read/Write
0
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Note: TCNT is write-protected by a password. For details see section 12.2.4, Notes on Register
Access.
When the TME bit is set to 1 in TCSR, TCNT starts counting pulses generated from an internal
clock source selected by bits CKS2 to CKS0 in TCSR. When the count overflows (changes from
H'FF to H'00), the OVF bit is set to 1 in TCSR. TCNT is initialized to H'00 by a reset and when
the TME bit is cleared to 0.
Rev. 2.00, 09/03, page 439 of 890