Datasheet

SAM9G20
DS60001516A-page 250  2017 Microchip Technology Inc.
23.2 Block Diagram
Figure 23-1: Block Diagram
23.3 Functional Description
23.3.1 Configuration
The PDC channel user interface enables the user to configure and control data transfers for each channel. The user interface of each PDC
channel is integrated into the associated peripheral user interface.
The user interface of a serial peripheral, whether it is full or half duplex, contains four 32-bit pointers (RPR, RNPR, TPR, TNPR) and four
16-bit counter registers (RCR, RNCR, TCR, TNCR). However, the transmit and receive parts of each type are programmed differently: the
transmit and receive parts of a full duplex peripheral can be programmed at the same time, whereas only one part (transmit or receive) of
a half duplex peripheral can be programmed at a time.
32-bit pointers define the access location in memory for current and next transfer, whether it is for read (transmit) or write (receive). 16-bit
counters define the size of current and next transfers. It is possible, at any moment, to read the number of transfers left for each channel.
PDC
FULL DUPLEX
PERIPHERAL
THR
RHR
PDC Channel A
PDC Channel B
Control
Status & Control
Control
PDC Channel C
HALF DUPLEX
PERIPHERAL
THR
Status & Control
RECEIVE or TRANSMIT
PERIPHERAL
RHR or THR
Control
Control
RHR
PDC Channel D
Status & Control