159
4317I–AVR–01/08
AT90PWM2/3/2B/3B
This signal can be selected between all falling or rising edge of PSCn0 or PSCn1 outputs.
In center aligned mode, OCRnRAH/L is not used, so it can be used to specified the synchroniza-
tion of the ADC. It this case, it’s minimum value is 1.
16.21 Interrupt Handling
As each PSC can be dedicated for one function, each PSC has its own interrupt system (vector
...)
List of interrupt sources:
•
Counter reload (end of On Time 1)
•
PSC Input event (active edge or at the beginning of level configured event)
•
PSC Mutual Synchronization Error
16.22 PSC Synchronization
2 or 3 PSC can be synchronized together. In this case, two waveform alignments are possible:
•
The waveforms are center aligned in the Center Aligned mode if master and slaves are all
with the same PSC period (which is the natural use).
•
The waveforms are edge aligned in the 1, 2 or 4 ramp mode
Figure 16-38. PSC Run Synchronization
If the PSCm has its PARUNn bit set, then it can start at the same time than PSCn-1.
PRUNn and PARUNn bits are located in PCTLn register.
See “PSC 0 Control Register – PCTL0”
See “PSC 1 Control Register – PCTL1” on page 166.
PARUN0
PRUN0
Run PSC0
PSC0
PARUN1
PRUN1
Run PSC1
PSC1
PARUN2
PRUN2
Run PSC2
PSC2
SY0Out
SY0In
SY1In
SY2In
SY1Out
SY2Out
