HD64F3039F18 Datasheet, PDF (242/710 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8 Family / H8/300H Series

Section 8 16-Bit Integrated Timer Unit (ITU)
8.2.7 Timer Counters (TCNT)
TCNT is a 16-bit counter. The ITU has five TCNTs, one for each channel.
Channel Abbreviation
0
TCNT0
1
TCNT1
2
TCNT2
3
TCNT3
4
TCNT4
Function
Up-counter
Phase counting mode: up/down-counter
Other modes: up-counter
Complementary PWM mode: up/down-counter
Other modes: up-counter
Bit
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Initial value 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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
Each TCNT is a 16-bit readable/writable register that counts pulse inputs from a clock source. The
clock source is selected by bits TPSC2 to TPSC0 in the timer control register (TCR).
TCNT0 and TCNT1 are up-counters. TCNT2 is an up/down-counter in phase counting mode and
an up-counter in other modes. TCNT3 and TCNT4 are up/down-counters in complementary PWM
mode and up-counters in other modes.
TCNT can be cleared to H'0000 by compare match with general register A or B (GRA or GRB) or
by input capture to GRA or GRB (counter clearing function) in the same channel.
When TCNT overflows (changes from H'FFFF to H'0000), the overflow flag (OVF) is set to 1 in
the timer status register (TSR) of the corresponding channel.
When TCNT underflows (changes from H'0000 to H'FFFF), the overflow flag (OVF) is set to 1 in
TSR of the corresponding channel.
The TCNTs are linked to the CPU by an internal 16-bit bus and can be written or read by either
word access or byte access.
Each TCNT is initialized to H'0000 by a reset and in standby mode.
Rev.3.00 Mar. 26, 2007 Page 218 of 682
REJ09B0353-0300