XMC-6VLX
USER’S MANUAL
Acromag, Inc. Tel: 248-295-0310
- 26 - http://www.acromag.com
- 26 -
www.acromag.com
CDMA Status Register (Read/Write) - (BAR0 + 0x000A0004)
This register provides status of the AXI CDMA.
Table 3.10:
CDMA Status
Register
Bit(s)
FUNCTION
0
This bit is reserved for future definition and will always return
zero.
1
CDMA Idle. Indicates the state of AXI CDMA operations.
When set and in Simple DMA mode, the bit indicates the
programmed transfer has completed and the CDMA is waiting
for a new transfer to be programmed. Writing to the “Bytes
to Transfer” register in Simple DMA mode causes the CDMA
to start (not Idle).
When set and in Scatter Gather mode, the bit indicates the
Scatter Gather Engine has reached the tail pointer for the
associated channel and all queued descriptors have been
processed. Writing to the tail pointer register automatically
restarts CDMA Scatter Gather operations.
0
Not Idle
1
CDMA is Idle
2
Reserved
3
Scatter Gather Included. This bit indicates if the AXI CDMA
has been implemented with Scatter Gather support included
(C_SG_ENABLE = 1). This is used by application software
(drivers) to determine if Scatter Gather Mode can be utilized.
0
Scatter Gather not included
1
Scatter Gather is included
4
DMA Internal Error. This bit indicates that an internal error
has been encountered by the DataMover on the data
transport channel. This error can occur if a 0 value Byte to
Transfer register is fed to the AXI DataMover or DataMover
has an internal processing error. A Bytes to Transfer register
value of 0 only happens if the register is written with zeros (in
Simple DMA mode) or a Bytes to Transfer register value of
zero is specified in the Control word of a fetched descriptor is
set to 0 (Scatter Gather Mode). This error condition causes
the AXI CDMA to gracefully halt. The CDMA Status register
bit-1 is set to ‘1’when the CDMA has completed shut down. A
reset (soft or hard) must be issued to clear the error
condition.
0
No CDMA Internal Errors
1
CDMA Internal Error detected. CDMA Engine halts.
5
DMA Slave Error. This bit indicates that an AXI slave error
response has been received by the AXI DataMover during an
AXI transfer (read or write). This error condition causes the
AXI CDMA to gracefully halt. The CDMA Status register bit-1 is
set to ‘1’ when the CDMA has completed shut down. A reset
(soft or hard) must be issued to clear the error condition.
