Operation Of 8/16-Bit Ppg Timer - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 17 8/16-BIT PPG TIMER
17.3

Operation of 8/16-bit PPG Timer

The 8/16-bit PPG timer has the 6 channels (PPG0, PPG1/PPG2, PPG3/PPG4, PPG5) of 8-
bit length PPG unit. Each of them can operate 3-type operations in total, the 8-bit
prescaler + 8-bit PPG modes and the 16-bit PPG mode by performing the direct-coupled
(PPG0 + PPG1/PPG2 + PPG3/PPG4 + PPG5) operations in addition to the independent
mode.
Outline of Operation of 8/16-bit PPG Timer
Each of 8-bit length PPG units has two 8-bit-length reload registers for the "L" and "H" sides (PRLL,
PRLH).
Values written in the PRLL and PRLH registers are reloaded to the 8-bit down counter (PCNT) for the "L"
and "H" sides alternately and down-counted at every count clock so that the output pin value is reversed
when the registers are reloaded at the count borrow occurrence. This operation causes the pin output to be
the "L"-width/"H"-width pulse output corresponding to the reload register value.
Operation is started/restarted by the written register bit.
The relation between the reload operation and the pulse output is shown in the following table.
In addition, when the bit 4 (PIE0) in PPGC0/PPGC2/PPGC4 is "1" and the bit 2 (PIE1) in PPGC1/PPGC3/
PPGC5 is "1", the interrupt request is output at a borrow occurrence from 00
to FFFF
H
Operating Mode
The 8/16-bit PPG timer has 3-type operation modes in total, the 2-channel independent mode, the 8-bit
prescaler + 8-bit PPG mode, and the 16-bit PPG mode (MB90330 series have 3 channels for each mode).
The 2-channel independent mode is a mode to allow an independent 2-channel operation as the 8-bit PPG.
The PPG outputs of ch0 and ch1 are connected to the PPG0 and PPG1 pins, respectively (PPG2 to PPG5
correspond to ch2 to ch5).
The 8-bit prescaler + 8-bit PPG mode is the operation mode to operate the ch0 (ch2/ch4) as the 8-bit
prescaler and to enable the 8-bit PPG waveform output in an arbiter cycle, by counting the ch1 (ch3/ch5) at
a ch0 (ch2/ch4) borrow output. The PPG0 (PPG2/PPG4) pin is connected to the bit prescaler output of ch0
(ch2/ch4) and the PPG1 pin is connected to the PPG output of ch1 (ch3/ch5).
The 16-bit PPG channel mode (MB90330 series provide 3 channels) is the operation mode to allow the
direct-coupling of ch0 and ch1 (direct-coupled chch2, ch3/ch4, ch5) to be operated as the 16-bit PPG. Both
PPG0 and PPG1 16-bit PPG power outputs are both connected.
416
Reload operation
PRLH → PCNT
in the 16-bit PPG mode) for respective counter.
Terminal output change
PPG0/PPG1 (0 → 1) rising
to FF
H
(borrow from 0000
H H