2.
Timer counter A (TCA)
TCA is an 8-bit read-only up-counter, which is incremented by internal clock input. The clock
source for input to this counter is selected by bits TMA3 to TMA0 in timer mode register A (TMA).
TCA values can be read by the CPU in active mode, but cannot be read in subactive mode. When
TCA overflows, the IRRTA bit in interrupt request register 1 (IRR1) is set to 1.
TCA is cleared by setting bits TMA3 and TMA2 of TMA to 11.
Upon reset, TCA is initialized to H'00.
3.
Clock stop register 1 (CKSTPR1)
CKSTPR1 is an 8-bit read/write register that performs module standby mode control for peripheral
modules. Only the bit relating to timer A is described here. For details of the other bits, see the
sections on the relevant modules.
Bit 0: Timer A module standby mode control (TACKSTP)
Bit 0 controls setting and clearing of module standby mode for timer A.
TACKSTP
Description
0
Timer A is set to module standby mode
1
Timer A module standby mode is cleared
(initial value)
—
TFCKSTP TCCKSTP TACKSTP
S31CKSTP S32CKSTP ADCKSTP TGCKSTP
7
6
5
4
3
2
1
0
1
1
1
1
1
1
1
1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit:
Initial value:
Read/Write:
Bit
Initial value
Read/Write
7
TCA7
0
R
6
TCA6
0
R
5
TCA5
0
R
4
TCA4
0
R
3
TCA3
0
R
0
TCA0
0
R
2
TCA2
0
R
1
TCA1
0
R
180