Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Data Sheet
Product codes
AT91SAM9M10-G45-EK
314
SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
These status flags are described in the Peripheral Status Register.
24.4.4
Data Transfers
The serial peripheral triggers its associated PDC channels’ transfers using transmit enable (TXEN) and receive
enable (RXEN) flags in the transfer control register integrated in the peripheral’s user interface.
enable (RXEN) flags in the transfer control register integrated in the peripheral’s user interface.
When the peripheral receives an external data, it sends a Receive Ready signal to its PDC receive channel which
then requests access to the Matrix. When access is granted, the PDC receive channel starts reading the peripheral
Receive Holding Register (RHR). The read data are stored in an internal buffer and then written to memory.
then requests access to the Matrix. When access is granted, the PDC receive channel starts reading the peripheral
Receive Holding Register (RHR). The read data are stored in an internal buffer and then written to memory.
When the peripheral is about to send data, it sends a Transmit Ready to its PDC transmit channel which then
requests access to the Matrix. When access is granted, the PDC transmit channel reads data from memory and
puts them to Transmit Holding Register (THR) of its associated peripheral. The same peripheral sends data
according to its mechanism.
requests access to the Matrix. When access is granted, the PDC transmit channel reads data from memory and
puts them to Transmit Holding Register (THR) of its associated peripheral. The same peripheral sends data
according to its mechanism.
24.4.5
PDC Flags and Peripheral Status Register
Each peripheral connected to the PDC sends out receive ready and transmit ready flags and the PDC sends back
flags to the peripheral. All these flags are only visible in the Peripheral Status Register.
flags to the peripheral. All these flags are only visible in the Peripheral Status Register.
Depending on the type of peripheral, half or full duplex, the flags belong to either one single channel or two differ-
ent channels.
ent channels.
24.4.5.1
Receive Transfer End
This flag is set when PERIPH_RCR register reaches zero and the last data has been transferred to memory.
It is reset by writing a non zero value in PERIPH_RCR or PERIPH_RNCR.
24.4.5.2
Transmit Transfer End
This flag is set when PERIPH_TCR register reaches zero and the last data has been written into peripheral THR.
It is reset by writing a non zero value in PERIPH_TCR or PERIPH_TNCR.
24.4.5.3
Receive Buffer Full
This flag is set when PERIPH_RCR register reaches zero with PERIPH_RNCR also set to zero and the last data
has been transferred to memory.
has been transferred to memory.
It is reset by writing a non zero value in PERIPH_TCR or PERIPH_TNCR.
24.4.5.4
Transmit Buffer Empty
This flag is set when PERIPH_TCR register reaches zero with PERIPH_TNCR also set to zero and the last data
has been written into peripheral THR.
has been written into peripheral THR.
It is reset by writing a non zero value in PERIPH_TCR or PERIPH_TNCR.