Notes On Dma Mode - Hitachi HD64411 Q2 User Manual

6 . 7

Notes on DMA Mode

1. Dummy memory read before DMA transfer
A dummy UGM read should be performed immediately before setting DMA transfer to the
UGM (DMA bits = 01).
2. Register access during DMA transfer
To read a Q2 register during DMA transfer to the UGM (DMA bits = 01), it is necessary to set
YUV = 01 for the YUV mode, then set DMA = 01 for the DMA mode, and start DMA transfer.
(Since the DMA bits are not set to 11, YUV conversion is not performed.)
As YUV = 01 is set for the YUV mode, the registers shown in the table below must not be
accessed
A [ 1 0 : 1 ] Register Abbreviation
007 IEMR
010 DMASHR
011 DMASLR
012 DMAWR
021 ISAHR
022 ISALR
023 IDSXR
024 IDSYR
025 IDER
026–0FF —
On completion of the DMA transfer, set YUV = 00 for the YUV mode and restore the Q2 to
normal mode.
166
Register Name
Input data conversion mode
DMA transfer start address
DMA transfer start address
DMA transfer word count
Image data transfer start address
Image data transfer start address
Image data size
Image data size
Image data entry
Reserved