h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 327

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

11.2
11.2.1
FRC is a 16-bit readable/writable up-counter that increments on an internal pulse generated from a
clock source. The clock source is selected by bits CKS1 and CKS0 in TCR.
FRC can also be cleared by compare-match A.
When FRC overflows from H'FFFF to H'0000, the overflow flag (OVF) in TCSR is set to 1.
FRC is initialized to H'0000 by a reset and in hardware standby mode.
11.2.2
OCRA and OCRB are 16-bit readable/writable registers, the contents of which are continually
compared with the value in the FRC. When a match is detected, the corresponding output compare
flags (OCFA or OCFB) is set in TCSR.
In addition, if the output enable bit (OEA or OEB) in TOCR is set to 1, when OCR and FRC
values match, the logic level selected by the output level bit (OLVLA or OLVLB) in TOCR is
output at the output compare pin (FTOA or FTOB). Following a reset, the FTOA and FTOB
output levels are 0 until the first compare-match.
OCR is initialized to H'FFFF by a reset and in hardware standby mode.
Read/
Read/
Bit
Initial
Bit
Initial
value
value
Write
Write
Register Descriptions
Free-Running Counter (FRC)
Output Compare Registers A and B (OCRA, OCRB)
R/W
R/W
15
15
0
1
R/W
R/W
14
14
0
1
R/W
R/W
13
13
0
1
R/W
R/W
12
12
0
1
R/W
R/W
11
11
0
1
R/W
R/W
10
10
0
1
R/W
R/W
9
0
9
1
R/W
R/W
8
0
8
1
R/W
R/W
Rev. 4.00 Jun 06, 2006 page 273 of 1004
7
0
7
1
Section 11 16-Bit Free-Running Timer
R/W
R/W
6
0
6
1
R/W
R/W
5
0
5
1
R/W
R/W
4
0
4
1
R/W
R/W
3
0
3
1
REJ09B0301-0400
R/W
R/W
2
0
2
1
R/W
R/W
1
0
1
1
R/W
R/W
0
0
0
1