HD6473847RHV Datasheet, PDF (251/546 Pages) Renesas Technology Corp – Renesas 8-Bit Single-Chip Microcomputer H8 Family / H8/300L Super Low Power Series

Section 9 Timers
Initial
Bit
Bit Name Value R/W Description
4
⎯
1
⎯
Reserved
This bit is always read as 1.
3
TMA3
0
R/W Internal Clock Select 3
Selects the operating mode of the timer A.
0: Functions as an interval timer to count the outputs of
prescaler S.
1: Functions as a clock-time base to count the outputs of
prescaler W.
2
TMA2
0
R/W Internal Clock Select 2 to 0
1
TMA1
0
R/W Select the clock input to TCA when TMA3 = 0.
0
TMA0
0
R/W 000: φ/8192
001: φ/4096
010: φ/2048
011: φ/512
100: φ/256
101: φ/128
110: φ/32
111: φ/8
These bits select the overflow period when TMA3 = 1
(when a 32.768 kHz crystal oscillator is used as φw).
000: 1 s
001: 0.5 s
010: 0.25 s
011: 0.03125 s
1XX: Both PSW and TCA are reset
Legend: X: Don't care.
Timer Counter A (TCA): TCA is an 8-bit readable 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 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 the interrupt request register 1 (IRR1) is set to 1. TCA is cleared
by setting bits TMA3 and TMA2 in TMA to B'11. TCA is initialized to H'00.
Rev. 7.00 Mar. 08, 2010 Page 219 of 510
REJ09B0024-0700