HD6475348R Datasheet, PDF (232/487 Pages) Hitachi Semiconductor – Single-Chip Microcomputer

The timer counter can be cleared by an external reset input or by an internal compare-match signal
generated at a compare-match event. Clock clear bits 1 and 0 (CCLR1 and CCLR0) of the timer
control register select the method of clearing.
When the timer counter overflows from H'FF to H'00, the overflow flag (OVF) in the timer
control/status register (TCSR) is set to 1.
The timer counter is initialized to H'00 at a reset and in the standby modes.
11.2.2 Time Constant Registers A and B (TCORA and TCORB)—H'FED2 and H'FED3
Bit
7
6
5
4
3
2
1
0
Initial value
Read/Write
1
1
1
1
1
1
1
1
R/W R/W R/W R/W R/W R/W R/W R/W
TCORA and TCORB are 8-bit readable/writable registers. The timer count is continually
compared with the constants written in these registers. When a match is detected, the
corresponding compare-match flag (CMFA or CMFB) is set in the timer control/status register
(TCSR).
The timer output signal (TMO) is controlled by these compare-match signals as specified by
output select bits 1 to 0 (OS1 to OS0) in the timer status/control register (TCSR).
TCORA and TCORB are initialized to H'FF at a reset and in the standby modes.
11.2.3 Timer Control Register (TCR)—H'FED0
Bit
Initial value
Read/Write
7
CMIEB
0
R/W
6
CMIEA
0
R/W
5
OVIE
0
R/W
4
3
CCLR1 CCLR0
0
0
R/W R/W
2
CKS2
0
R/W
1
CKS1
0
R/W
0
CKS0
0
R/W
The TCR is an 8-bit readable/writable register that selects the clock source and the time at which
the timer counter is cleared, and enables interrupts.
The TCR is initialized to H'00 at a reset and in the standby modes.
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