Chapter 9: DMA Controller
TX7901 User’s Manual (Rev. 6.30T – Nov, 2001)
9-11
Table 9-3 Channel Control Register Field Descriptions
Bit(s)
Field
R/W
Default
Description
63:25
–
R/O
0
Reserved (0)
24
EN
R/W
0
DMA Channel Enable (0)
This bit enables this DMA channel.
0 - Disable the DMA channel.
1 - Enable the DMA channel.
23
STRT
R/W
0
DMA Channel Start (0)
This bit is reset automatically once the DMA channel is granted in normal
mode or upon the transfer completion of the entire block of data in the chain
mode. Writing a “1” sets this bit. 0s written to this bit are ignored.
0 - Ignored
1 - Software DMA request
22:19
FPL
R/W
0
Fixed Priority Level (0000)
The fixed priority level is used when the DMA channel is programmed to work
with fixed priority GCSR[FRP]=0. Level 0 is the highest priority whereas level
15 is the lowest. If several channels have the same priority, the channel with
the lowest physical request number will be granted access. For example, if
both DMA Channel 1 and DMA Channel 5 request access at the same time
and are at the same priority level, DMA Channel 1 will be granted access.
0000 - Level 0
0001 - Level 1
0010 - Level 2
0011 - Level 3
0100 - Level 4
0101 - Level 5
0110 - Level 6
0111 - Level 7
1000 - Level 8
1001 - Level 9
1010 - Level 10
1011 - Level 11
1100 - Level 12
1101 - Level 13
1110 - Level 14
1111 - Level 15
18
CCS
R/W
0
C790 Cycle Stealing (0)
Setting this bit enables the DMAC to allow the C790 to perform cycle
stealing. This feature is used to synchronize the data between the DMAC
and the C790. Other bus masters are always allowed to perform cycle
stealing to minimize the master request-to-grant latency while the DMAC is
the master on the C790 bus or the G-Bus.
0 - No cycle stealing
1 - Cycle stealing
17
SLC
R/W
0
Block/Slice Transfer (0)
If this bit is set, the DMA channel will transfer a slice of data for a DMA
hardware request (dmaReqB) or a DMA software request (STRT). If this bit
is reset, the DMA channel will transfer the entire block of data for a DMA
hardware or software request.
0 - Block transfer
1 - Slice transfer
16:14
SLS
R/W
0
Slice Size (000)
The slice size is used only when SLC is set.
000 - 1 quad-word
001 - 2 quad-words
010 - 3 quad-words
011 - 4 quad-words
100 - 5 quad-words
Summary of Contents for TMPR7901
Page 1: ...TX System RISC TX79 Family TMPR7901 Symmetric 2 way superscalar 64 bit CPU ...
Page 14: ...Handling Precautions ...
Page 15: ......
Page 17: ...1 Using Toshiba Semiconductors Safely 1 2 ...
Page 41: ...4 Precautions and Usage Considerations 4 2 ...
Page 42: ...TX7901 User s Manual Rev 6 30T November 2001 DOCUMENT NUMBER M 99 00004 07 ...
Page 43: ......
Page 259: ...Chapter 13 Removed TX7901 User s Manual Rev 6 30T Nov 2001 13 1 13 Removed ...
Page 260: ...Chapter 13 Removed TX7901 User s Manual Rev 6 30T Nov 2001 13 2 ...