SH7052 datasheet(332/919 Pages) RENESAS

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10.2.15

Free-Running Counters (TCNT)

The free-running counters (TCNT) are 32- or 16-bit up- or up/down-counters. The ATU-II has 17

TCNT counters: one 32-bit TCNT in channel 0, and sixteen 16-bit TCNTs in each of channels 1 to

7 and 11.

Channel

Abbreviation

Function

TCNT0H, TCNT0L

32-bit up-counter (initial value H’00000000)

TCNT1A, TCNT1B

16-bit up-counters (initial value H'0000)

TCNT2A, TCNT2B

TCNT3

TCNT4

TCNT5

TCNT6A to TCNT6D

16-bit up/down-counters (initial value H'0001)

TCNT7A to TCNT7D

16-bit up-counters (initial value H'0001)

TCNT11

16-bit up-counter (initial value H'0000)

Free-Running Counter 0 (TCNT0H, TCNT0L): Free-running counter 0 (comprising TCNT0H

and TCNT0L) is a 32-bit readable/writable register that counts on an input clock. When the bits

corresponding to the timer start register 1 (TSTR1) are set to 1, this counter starts to count. The

input clock is selected with prescaler register 1 (PSCR1).

Bit:

Initial value:

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 R/W

Bit:

Initial value:

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 R/W

When TCNT0 overflows (from H'FFFFFFFF to H'00000000), the OVF0 overflow flag in the

timer status register (TSR0) is set to 1.

TCNT0 can only be accessed by a longword read or write. Word reads or writes cannot be used.

TCNT0 is initialized to H'00000000 by a power-on reset, and in hardware standby mode and

software standby mode.

SH7052 Datasheet(PDF) 332 Page - Renesas Technology Corp