AT90PWM2B-16SE ATMEL [ATMEL Corporation], AT90PWM2B-16SE Datasheet - Page 159

• Manufacturer Part Number: AT90PWM2B-16SE
• Description: 8-bit Microcontroller with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

16.22.1
16.23 PSC Clock Sources
4317J–AVR–08/10
Fault events in Autorun mode
Note : Do not set the PARUNn bits on the three PSC at the same time.
Thanks to this feature, we can for example configure two PSC in slave mode (PARUNn = 1 /
PRUNn = 0) and one PSC in master mode (PARUNm = 0 / PRUNm = 0). This PSC master can
start all PSC at the same moment ( PRUNm = 1).
To complete this master/slave mechanism, fault event (input mode 7) is propagated from PSCn-
1 to PSCn and from PSCn to PSCn-1.
A PSC which propagate a Run signal to the following PSC stops this PSC when the Run signal
is deactivate.
According to the architecture of the PSC synchronization which build a “daisy-chain on the PSC
run signal” beetwen the three PSC, only the fault event (mode 7) which is able to “stop” the PSC
through the PRUN bits is transmited along this daisy-chain.
A PSC which receive its Run signal from the previous PSC transmits its fault signal (if enabled)
to this previous PSC. So a slave PSC propagates its fault events when they are configured and
enabled.
PSC must be able to generate high frequency with enhanced resolution.
Each PSC has two clock inputs:
•
•
Figure 16-39. Clock selection
PCLKSELn bit in PSC n Configuration register (PCNFn) is used to select the clock source.
PPREn1/0 bits in PSC n Control Register (PCTLn) are used to select the divide factor of the
clock.
CLK PLL from the PLL
CLK I/O
CLK
CLK
PLL
I/O
(1) : CK/16 for AT90PWM2/3
(2) : CK/64 for AT90PWM2/3
PCLKSELn
1
0
CK
PRESCALER
AT90PWM2/3/2B/3B
CLK
PSCn
PPREn1/0
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