168
TCFH and TCFL can be read and written by the CPU, but in 16-bit mode, data transfer with the
CPU takes place via a temporary register (TEMP). For details see 9.3.3, Interface with the CPU.
Upon reset, TCFH and TCFL are each initialized to H'00.
16-Bit Mode (TCF): 16-bit mode is selected by clearing bit CKSH2 to 0 in timer control register
F (TCRF). The TCF input clock is selected by TCRF bits CKSL2 to CKSL0.
Timer control status register F (TCSRF) can be set so that counter TCF will be cleared by compare
match.
When TCF overflows from H'FFFF to H'0000, the overflow flag (OVFH) in TCSRF is set to 1. If
bit OVIEH in TCSRF is set to 1 when an overflow occurs, bit IRRTFH in interrupt request register
2 (IRR2) will be set to 1; and if bit IENTFH in interrupt enable register 2 (IENR2) is set to 1, a
CPU interrupt will be requested.
8-Bit Mode (TCFH, TCFL): When bit CKSH2 in timer control register F (TCRF) is set to 1,
timer F functions as two separate 8-bit counters, TCFH and TCFL. The TCFH (TCFL) input clock
is selected by TCRF bits CKSH2 to CKSH0 (CKSL2 to CKSL0).
TCFH (TCFL) can be cleared by a compare match signal. This designation is made in bit CCLRH
(CCLRL) in TCSRF.
When TCFH (TCFL) overflows from H'FF to H'00, the overflow flag OVFH (OVFL) in TCSRF is
set to 1. If bit OVIEH (OVIEL) in TCSRF is set to 1 when an overflow occurs, bit IRRTFH
(IRRTHL) in interrupt request register 2 (IRR2) will be set to 1; and if bit IENTFH (IENTFL) in
interrupt enable register 2 (IENR2) is set to 1, a CPU interrupt will be requested.
16-Bit Output Compare Register (OCRF)
8-Bit Output Compare Register (OCRFH)
8-Bit Output Compare Register (OCRFL)
OCRF
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Initial value
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Read/Write
R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W
OCRFH
OCRFL
OCRF is a 16-bit read/write output compare register consisting of two 8-bit read/write registers
OCRFH and OCRFL. It can be used as a 16-bit output compare register, with OCRFH as the