at91sam9g20-cu ATMEL Corporation, at91sam9g20-cu Datasheet - Page 520

• Manufacturer Part Number: at91sam9g20-cu
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

33.6.1.3
520
AT91SAM9G20 Preliminary
Receiver Clock Management
The transmitter can also drive the TK I/O pad continuously or be limited to the actual data trans-
fer. The clock output is configured by the SSC_TCMR register. The Transmit Clock Inversion
(CKI) bits have no effect on the clock outputs. Programming the TCMR register to select TK pin
(CKS field) and at the same time Continuous Transmit Clock (CKO field) might lead to unpredict-
able results.
Figure 33-6. Transmitter Clock Management
The receiver clock is generated from the transmitter clock or the divider clock or an external
clock scanned on the RK I/O pad. The Receive Clock is selected by the CKS field in
SSC_RCMR (Receive Clock Mode Register). Receive Clocks can be inverted independently by
the CKI bits in SSC_RCMR.
The receiver can also drive the RK I/O pad continuously or be limited to the actual data transfer.
The clock output is configured by the SSC_RCMR register. The Receive Clock Inversion (CKI)
bits have no effect on the clock outputs. Programming the RCMR register to select RK pin (CKS
field) and at the same time Continuous Receive Clock (CKO field) can lead to unpredictable
results.
Receiver
TK (pin)
Divider
Clock
Clock
MUX
CKS
CKO
Controller
Tri_state
MUX
INV
CKI
Data Transfer
Controller
Tri-state
CKG
6384B–ATARM–15-Dec-08
Transmitter
Clock
Clock
Output