H8S2378 Datasheet, PDF (720/1203 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2300 Series

Section 13 8-Bit Timers (TMR)
13.3.1 Timer Counter (TCNT)
TCNT is 8-bit up-counter. TCNT_0 and TCNT_1 comprise a single 16-bit register so they can be
accessed together by a word transfer instruction. Bits CKS2 to CKS0 in TCR are used to select a
clock. TCNT can be cleared by an external reset input or by a compare match signal A or B.
Which signal is to be used for clearing is selected by bits CCLR1 and CCLR0 in TCR. When
TCNT overflows from H'FF to H'00, OVF in TCSR is set to 1. TCNT is initialized to H'00.
13.3.2 Time Constant Register A (TCORA)
TCORA is 8-bit readable/writable register. TCORA_0 and TCORA_1 comprise a single 16-bit
register so they can be accessed together by a word transfer instruction.
The value in TCORA is continually compared with the value in TCNT. When a match is detected,
the corresponding CMFA flag in TCSR is set to 1. Note, however, that comparison is disabled
during the T₂ state of a TCORA write cycle.
The timer output from the TMO pin can be freely controlled by this compare match signal
(compare match A) and the settings of bits OS1 and OS0 in TCSR.
TCORA is initialized to H'FF.
13.3.3 Time Constant Register B (TCORB)
TCORB is 8-bit readable/writable register. TCORB_0 and TCORB_1 comprise a single 16-bit
register so they can be accessed together by a word transfer instruction.
TCORB is continually compared with the value in TCNT. When a match is detected, the
corresponding CMFB flag in TCSR is set to 1. Note, however, that comparison is disabled during
the T₂ state of a TCOBR write cycle.
The timer output from the TMO pin can be freely controlled by this compare match signal
(compare match B) and the settings of bits OS3 and OS2 in TCSR.
TCORB is initialized to H'FF.
Rev. 6.00 Jul 19, 2006 page 656 of 1136
REJ09B0109-0600