32.4.4 Data Transfers

The PDC channel first access is triggered when the peripheral is enabled.

When the peripheral receives external data, it sends a trigger event to its PDC receive channel which then requests access to the system bus matrix. When access is granted, the PDC receive channel reads the data in the peripheral. The read data are stored in an internal buffer of the PDC and then written to memory.

When the peripheral is ready to send data, it sends a trigger event to its PDC transmit channel which then requests access to the system bus matrix. When access is granted, the PDC transmit channel reads data from memory and transfers the data to the associated peripheral.

In case of invalid memory address resulting from a badly programmed PDC transmit or receive pointer, the system bus matrix does not perform the requested access and signals a bus error to the PDC. This transfer bus error drives the PERIPH_PTSR.ERR bit high to flag the error in the Transfer Status register.