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CHAPTER 16 8-/16-BIT PPG TIMER
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Details of pins in block diagram
Table 16.2-1 lists the actual pin names and interrupt request numbers of the 8-/16-bit PPG timer.
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PPG operation mode control register C (PPGCC)
This register enables or disables operation of the 8-/16-bit PPG timer, pin output and an underflow
interrupt. It also indicates the occurrence of an underflow.
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PPGC/D count clock select register (PPGCD)
This register sets the count clock of the 8-/16-bit PPG timer and switching the output pin between PPGC
and PPGD.
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PPGC reload registers (PRLHC, PRLLC)
These registers set the High width or Low width of the output pulse. The values set in these registers are
reloaded to the PPGC down counter (PCNTC) when the 8-/16-bit PPG timer is started.
●
PPGC down counter (PCNTC)
This counter is an 8-bit down counter that alternately reloads the values set in the PPGC reload registers
(PRLHC and PRLLC) to decrement. When an underflow occurs, the pin output is inverted. The 2-channel
PPG down counters (PPGC and PPGD) can also be concatenated for use as a single-channel 16-bit PPG
down counter.
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PPGC temporary buffer (PRLBHC)
This buffer prevents deviation of the output pulse width caused at writing to the PPG reload registers
(PRLHC and PRLLC). This buffer stores the PRLHC value temporarily and enables it in synchronization
with the timing of writing to the PRLLC.
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Reload register L/H selector
This selector detects the current pin output level to select which register value, Low reload register
(PRLLC) or High reload register (PRLHC), should be reloaded to the PPGC down counter.
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Count clock selector
This selector selects the count clock to be inputted to the PPGC down counter from five frequency-divided
clocks of the machine clock or the frequency-divided clocks of the timebase timer.
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PPG output control circuit
This circuit inverts the pin output level and the output when an underflow occurs.
Table 16.2-1 Pins and Interrupt Request Numbers in Block Diagram
Channel Output Pin Interrupt Request
Number
PPG:REV=0 PPG:REV=1
PPGC P66 / PPGC P22 / PPGD
#23 (17
H
)
PPGD P22 / PPGD P66 / PPGC
PPGE P67/ PPGE P23 / PPGF
#24 (18
H
)
PPGF P23/ PPGF P67 / PPGE