Table 9-11. Primary and Alternate Channel Control Structure Offsets for Channel 8
Description
Offset
Channel 8 Primary Source End Pointer
Control Table Base + 0x080
Channel 8 Primary Destination End Pointer
Control Table Base + 0x084
Channel 8 Primary Control Word
Control Table Base + 0x088
Channel 8 Alternate Source End Pointer
Control Table Base + 0x280
Channel 8 Alternate Destination End Pointer
Control Table Base + 0x284
Channel 8 Alternate Control Word
Control Table Base + 0x288
Configure the Source and Destination
The source and destination end pointers must be set to the last address for the transfer (inclusive).
Because the peripheral pointer does not change, it simply points to the peripheral's data register.
Both the primary and alternate sets of pointers must be configured.
1.
Program the primary source end pointer at offset 0x080 to the address of the peripheral's receive
buffer.
2.
Program the primary destination end pointer at offset 0x084 to the address of ping-pong buffer
A + 0x3F.
3.
Program the alternate source end pointer at offset 0x280 to the address of the peripheral's
receive buffer.
4.
Program the alternate destination end pointer at offset 0x284 to the address of ping-pong buffer
B + 0x3F.
The primary control word at offset 0x088 and the alternate control word at offset 0x288 are initially
programmed the same way.
1.
Program the primary channel control word at offset 0x088 according to Table 9-12.
2.
Program the alternate channel control word at offset 0x288 according to Table 9-12.
Table 9-12. Channel Control Word Configuration for Peripheral Ping-Pong Receive Example
Description
Value
Bits
Field in DMACHCTL
8-bit destination address increment
0
31:30
DSTINC
8-bit destination data size
0
29:28
DSTSIZE
Source address does not increment
3
27:26
SRCINC
8-bit source data size
0
25:24
SRCSIZE
Reserved
0
23:22
reserved
Privileged access protection for
destination data writes
0
21
DSTPROT0
Reserved
0
20:19
reserved
Privileged access protection for source
data reads
0
18
SRCPROT0
Arbitrates after 8 transfers
3
17:14
ARBSIZE
Transfer 64 items
63
13:4
XFERSIZE
N/A for this transfer type
0
3
NXTUSEBURST
Use Ping-Pong transfer mode
3
2:0
XFERMODE
699
June 18, 2014
Texas Instruments-Production Data
Tiva
™
TM4C1294NCPDT Microcontroller