SH7055S Datasheet, PDF (347/1002 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7000 Series

11.2.11 Down-Count Start Register (DSTR)
The down-count start register (DSTR) is a 16-bit register. The ATU-II has one DSTR register in
channel 8.
Bit: 15
14
13
12
11
DST8P DST8O DST8N DST8M DST8L
Initial value: 0
0
0
0
0
R/W: R/W* R/W* R/W* R/W* R/W*
10
DST8K
0
R/W*
9
DST8J
0
R/W*
8
DST8I
0
R/W*
Bit:
Initial value:
R/W:
7
DST8H
0
R/W*
6
DST8G
0
R/W*
5
DST8F
0
R/W*
4
DST8E
0
R/W*
3
DST8D
0
R/W*
2
DST8C
0
R/W*
1
DST8B
0
R/W*
0
DST8A
0
R/W*
Note: * Only 1 can be written.
DSTR is a 16-bit readable/writable register that starts the channel 8 down-counter (DCNT).
When the one-shot pulse function is used, a value of 1 can be set in a DST8x bit at any time by the
user program, except when the corresponding DCNT8x value is H'0000. The DST8x bits are
cleared to 0 automatically when the DCNT value overflows.
When the offset one-shot pulse function is used, DST8x is automatically set to 1 (except when the
DCNT8x value is H'0000) when a compare-match occurs between the channel 1 or 2 free-running
counter (TCNT) and a general register (GR) or the output compare register (OCR1) while the
corresponding timer connection register (TCNR) bit is set to 1. As regards DST8I to DST8P, if the
RLDEN bit in the reload enable register (RLDENR) is set to 1 and the reload register (RLDR8)
value is not H'0000, a reload is performed into the corresponding DCNT8x, and the DST8x bit is
set to 1. DST8x is automatically cleared to 0 when the DCNT8x vaue underflows, or by input of a
channel 1 or 2 one-shot terminate trigger signal set in the trigger mode register (TRGMDR) while
the corresponding one-shot pulse terminate register (OTR) bit is set to 1, whichever occurs first.
DCNT8x is cleared to H'0000 when underflow occurs.
DSTR is initialized to H'0000 by a power-on reset, and in hardware standby mode and software
standby mode.
For details, see sections 11.3.5, One-Shot Pulse Function, and 11.3.6, Offset One-Shot Pulse
Function and Output Cutoff Function.
Rev.2.0, 07/03, page 309 of 960