Selecting A Count Clock - Fujitsu F2MC-16LX Hardware Manual

12.4.3 Selecting a Count Clock

As the count clock used for 8/16-bit PPG operation, machine clock and time-based
counter inputs can be used. Six types of count clock input is selectable. The clock for
ch.0 is selected by the PCM2 to PCM0 bits of the PPGE register, and the clock for ch.1
is selected by the PCS2 to PCS0 bits. The clock signal can be selected from the clocks
produced by dividing the machine clock by 16 to 1 and the time-based timer input.
In the 8-bit prescaler + 8-bit PPG mode and the 16-bit PPG 1-ch mode, however, the
PPG unit on ch.1 operates with the count clock signal input from ch.0. Therefore, the
value of the PCS1 bit in the PPGC1 register is ignored.
■ Notes on Selecting a Count Clock
When the time-based timer input is used, the first count cycle when PPG operation is triggered
and the first count cycle after PPG operation is stopped may be shifted. In addition, when the
time-based counter is cleared during operation of this module, a cycle shift may occur.
In the 8-bit prescaler plus 8-bit PPG mode, when ch.0 is operating and ch.1 is in the stopped
state, starting ch.1 may shift the first count cycle.
12.4 8/16-Bit PPG Operation
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