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Section 10 16-Bit Free-Running Timer (FRT)
10.2.3
Output Compare Registers AR and AF (OCRAR and OCRAF)
OCRAR and OCRAF are 16-bit readable/writable registers. They are accessed when the ICRS bit
in TOCR is set to 1. When the OCRAMS bit in TOCR is set to 1, the operation of OCRA is
changed to include the use of OCRAR and OCRAF. The contents of OCRAR and OCRAF are
automatically added alternately to OCRA, and the result is written to OCRA. The write operation
is performed on the occurrence of compare-match A. In the 1st compare-match A after setting the
OCRAMS bit to 1, OCRAF is added. The operation due to compare-match A varies according to
whether the compare-match follows addition of OCRAR or OCRAF.
When using the OCRA automatic addition function, do not select internal clock φ/2 as the FRC
input clock together with a set value of H'0001 or less for OCRAR (or OCRAF).
OCRAR and OCRAF should always be accessed in 16-bit units; cannot be accessed in 8-bit units.
OCRAR and OCRAF are initialized to H'FFFF.
Rev. 1.00 Mar. 12, 2008 Page 376 of 1178
REJ09B0403-0100
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