Fujitsu F2MC-16LX Hardware Manual page 434

CHAPTER 17 8/16-BIT PPG TIMER
Count Clock Selection
The count clock used for 8/16-bit PPG timer operation uses the peripheral clock and the time base counter
input to allow 6 types of count clock input selection.
The bit4 to bit2 (PCM2 to PCM0) of PPG01/PPG23/PPG45 register selects the ch0 (ch2/ch4) clock and the
bit7 to bit5 (PCS2 to PCS0) of PPG01/PPG23/PPG45 register selects the ch1 (ch3/ch5) clock.
For the clock selection, 1/16 to 1 times of machine clock and the time base counter input are selected.
Notes:
• The bit 14 (PCS1) value of PPGC1 register is invalid in the 8-bit prescaler + 8-bit PPG mode and
16-bit PPG mode.
• When the time base timer input is used, the trigger or the first count cycle after stopping may
deviate. In addition, if the time base counter is initialized in the 8/16-bit PPG timer operation, the
cycle may deviate.
• When the ch0/ch2/ch4 is in the operating status, the ch1/ch3/ch5 is in the stopped status, and the
ch1 (ch3/ch5) is started in the 8-bit prescaler + 8-bit PPG mode, the first count cycle may deviate.
Pin Output Control of Pulse
The pulse generated by the 8/16-bit PPG timer can be output from the external pins (PPG0 to PPG5). To
output pulses from the external pin, "1" is written in the bit corresponding to each terminal. The PPGC0 bit
5 (PE0) and the PPGC1 bit 3 (PE1) are used for the PPG0/PPG2/PPG4 and PPG1/PPG3/PPG5 pins,
respectively. When "0" is written in this terminal (initial value), no pulse is output from the external pin
that then functions as a general-purpose port.
Since the same waveform is output from the PPG0 to PPG5 in the 16-bit PPG mode, either of external pins
can be enabled to obtain the same output.
The 8-bit prescaler toggle waveform and the 8-bit PPG waveform are output from the PPG0/PPG2/PPG4
and the PPG1/PPG3/PPG5, respectively, in the 8-bit prescaler + 8-bit PPG mode.
The output waveform in this mode is shown in Figure 17.3-2.
P
PPG0
PPG1
The pulse width shown in Figure 17.3-2 can be calculated by the following expression.
418
Figure 17.3-2 8 + 8PPG Output Operation Waveform
0 P 0
H L
P 1
H
P 1
L