
Hardware Description
MFC 2000 Multifunctional Peripheral Controller 2000
100723A
Conexant
24-11
ARM access to the ABI buffers are provided for diagnostic purposes only and should not be used as part of
normal operation.
When the ARM makes an access to these buffers, the ARM is held off and clock domain synchronization occurs
before the access is completed. As a result, a significant wait state penalty is incurred. This penalty will be even
longer if a local DMA operation is in progress when the access is made as the ARM is held off for both the clock
domain synchronization and the completion of the local DMA transfer.
There is a risk of data corruption when the ARM makes write accesses to these buffers while a DMA transfer is in
progress. This can occur because the buffers alternate betweeen a DMA transfer sequence in the ARM Bus
Subsystem domain and a DMA transfer sequence in the
Countach
Bus Subsystem domain. If the write operation
occurs between these DMA transfers, the DMA data in the buffer will be replaced with the ARM data.
24.4 Countach Imaging DSP Subsystem Interface
ARM as either bytes or halfwords.
The buffer is located at the following addresses:
Address:
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Default:
Countach DMA
Buffer
(CSIDmaBuf)
$01FF830x
CSI Buffer
Data [15]
CSI Buffer
Data [14]
CSI Buffer
Data [13]
CSI Buffer
Data [12]
CSI Buffer
Data [11]
CSI Buffer
Data [10]
CSI Buffer
Data [9]
CSI Buffer
Data [8]
Rst. Value
00h
Read Value
00h
Address:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Default:
Countach DMA
Buffer
(CSIDmaBuf)
$01FF830x
CSI Buffer
Data [7]
CSI Buffer
Data [6]
CSI Buffer
Data [5]
CSI Buffer
Data [4]
CSI Buffer
Data [3]
CSI Buffer
Data [2]
CSI Buffer
Data [1]
CSI Buffer
Data [0]
Rst Value
00h
Read Value
00h
Table 24-1. Needs a title
$01FF8300-01
CSI DMA Buffer halfword 0
$01FF8302-03
CSI DMA Buffer halfword 1
$01FF8304-05
CSI DMA Buffer halfword 2
$01FF8306-07
CSI DMA Buffer halfword 3
$01FF8306-07
CSI DMA Buffer halfword 4
$01FF8306-07
CSI DMA Buffer halfword 5
$01FF8306-07
CSI DMA Buffer halfword 6
$01FF8306-07
CSI DMA Buffer halfword 7
ARM access to the CSI buffers are provided for diagnostic purposes only and should not be used as part of
normal operation.
When the ARM makes an access to these buffers, the ARM is held off and clock domain synchronization occurs
before the access is completed. As a result, a significant wait state penalty is incurred. This penalty will be even
longer if a local DMA operation is in progress when the access is made as the ARM is held off for both the clock
domain synchronization and the completion of the local DMA transfer.
There is a risk of data corruption when the ARM makes write accesses to this buffer while a DMA transfer is in
progress. It is also possible that an access to this buffer can cause spurious writes to the scratchpad space while
a DMA transfer is in progress.