Hitachi H8/326 Series, Hardware Manual

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Bits 2, 1, and 0—Clock Select (CKS2, CKS1, and CKS0): These bits and bits ICKS1 and
ICKS0 in the serial/timer control register (STCR) select the internal or external clock source for the
timer counter. Six internal clock sources, derived by prescaling the system clock, are available for
each timer channel. For internal clock sources the counter is incremented on the falling edge of the
internal clock. For an external clock source, these bits can select whether to increment the counter
on the rising or falling edge of the clock input, or on both edges.
TCR STCR
Bit 2 Bit 1 Bit 0 Bit 1 Bit 0
Channel CKS2 CKS1 CKS0 ICKS1 ICKS0 Description
0 0 0 0 — — No clock source (timer stopped) (Initial value)
0 0 1 — 0 Ø/8 internal clock, counted on falling edge
0 0 1 — 1 Ø/2 internal clock, counted on falling edge
0 1 0 — 0 Ø/64 internal clock, counted on falling edge
0 1 0 — 1 Ø/32 internal clock, counted on falling edge
0 1 1 — 0 Ø/1024 internal clock, counted on falling edge
0 1 1 — 1 Ø/256 internal clock, counted on falling edge
1 0 0 — — No clock source (timer stopped)
1 0 1 — — External clock source, counted on rising edge
1 1 0 — — External clock source, counted on falling edge
1 1 1 — — External clock source, counted on both rising
and falling edges
1 0 0 0 — — No clock source (timer stopped) (Initial value)
0 0 1 0 — Ø/8 internal clock, counted on falling edge
0 0 1 1 — Ø/2 internal clock, counted on falling edge
0 1 0 0 — Ø/64 internal clock, counted on falling edge
0 1 0 1 — Ø/128 internal clock, counted on falling edge
0 1 1 0 — Ø/1024 internal clock, counted on falling edge
0 1 1 1 — Ø/2048 internal clock, counted on falling edge
1 0 0 — — No clock source (timer stopped)
1 0 1 — — External clock source, counted on rising edge
1 1 0 — — External clock source, counted on falling edge
1 1 1 — — External clock source, counted on both rising
and falling edges
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