Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
519
Application DMA Unit—Intel
®
81341 and 81342
5.14
Error Conditions
5.14.1
Fatal Errors
Internal Interface Parity Errors, Internal Bus Master-Abort, Internal Bus Target-Abort,
and the MCU Port Abort are fatal errors that are recorded by the Application DMA. In
addition, when the Status Write Back Enable in the ADCR is cleared, the Zero Result
Buffer Error is recorded as a fatal error by the Application DMA.
When a fatal error occurs, the actions taken are detailed below:
• The ADMA shall cease the ongoing transfer for the current chain descriptor and
clear the
Application DMA Active
flag in the ACSR.
• The ADMA does not read any new chain descriptors.
• The ADMA sets the error flag in the ADMA Status Register. For example; when an
Internal Bus master-abort occurred during a transfer, the channel sets bit 5 in the
ACSR.
• The ADMA signals an interrupt to the Intel XScale
®
processor and clears the ADMA
Enable bit in the ACCR.
• The Application DMA does not restart the transfer after an error condition. It is the
responsibility of the application software to reconfigure the ADMA to complete any
remaining transfers.
Note:
Target-aborts during ADMA reads result either from multi-bit ECC errors that are
recorded by the MCU or target abort conditions from the host I/O interface which are
recorded by the host I/O interface. The ADMA needs to be re-enabled by writing a 1 to
the ADMA Enable bit before initiating a new operation.
5.14.2
Non-Fatal Errors
When the Status Write Back Enable in the ADCR is set, the Zero Result Buffer Error is
handled as a non-fatal error by the Application DMA.
When a non-fatal error occurs, the actions taken are detailed below:
• The ADMA prepare the Transfer Status field of the ABCR by setting the Transfer
Complete bit and the appropriate error bit
• The ADMA writes the ABCR back to the descriptor pointed to by the ADAR.
22
• The ADMA begins processing the next chain descriptor(s), when any.
5.15
Power-Up/Default Status
Upon power-up, an external hardware reset, the Application DMA Registers are
initialized to their default values.
22.When the Status Write Back Enable bit is set for a descriptor, the ABCR is written back to memory
with the Transfer Complete bit set whether or not a non-fatal error has occurred.