HD64F2149 Datasheet, PDF (335/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

11.2 Register Descriptions
11.2.1 Free-Running Counter (FRC)
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
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 Output Compare Registers A and B (OCRA, OCRB)
Bit
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Initial value 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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
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.
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