402-00005-00
Registers
3–68
Rev 02; February 8, 2002
3.5.2 Bus Master Control (BMCTLX) R/W
0
7
BADR3 + 0x010
SCANDIR
CLIPEN
PADEN
BMZOOM1
BMZOOM0
BMBYTE
BMSHIFT
BMEN
8
15
DMA
DMA
DMA
DMA
DMA
DMA
DMA
DMA
PCP_BMCTLX_32
16
23
Reserved
DMA
DMA
DMA
DMA
DMA
DMA
DMA
24
31
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
SEL
START14
START12
START12
START11
START10
START9
START8
START7
START6
START5
START4
START3
START2
START1
START0
This register enables bus master transfer of image memory data, and controls the formatting.
Bit
Mnemonic
Function
0
BMEN
Bus Master Enable
1
BMSHIFT
Bus Master Data Shift Enable
1
BMBYTESEL
Bus Master Byte Lane Select
3–4
BMZOOM
Bus Master Zoom
5
PADEN
Pad Enable
6
CLIPEN
Clip Enable
7
SCANDIR
Bus Master Scan Direction
8–22
DMASTART
DMA Table Start Address
23–31
Reserved
“Don’t care”
3.5.2.1 Bus Master Enable (BMEN) R/W
The BMEN bit enables the bus master port for a memory data transfer onto the PCI-bus. BMEN should be disabled
prior to changing any of the other bus master settings, to avoid affecting a current bus master operation. This bit must
be zero during host read or write access to the image memory buffer.
BMEN
Function
0
Disable Bus Master port
1
Request a transfer to the BMC
3.5.2.2 Bus Master Data Shift Enable (BMSHIFT) R/W
The BMSHIFT bit is only valid in 12-bit input mode (INMODE=1). This bit has no effect in 8-bit mode. In 12-bit
mode, enabling this bit left-shifts the input data by four bit positions. Bit 11 of the input data gets shifted into bit
position 15. Bit 0 of the input data gets shifted into bit position 4. This is also called “normalizing to 16 bits.” The 4
lsbs (least significant bits) are don’t care after the shift. This bit is ignored if BMZOOM = 0x03 or if PADEN is en-
abled.
BMSHIFT
Function
0
Disable shift
1
Enable shift: left-shift 4
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com