MC68HC708XL36 FREESCALE [Freescale Semiconductor, Inc], MC68HC708XL36 Datasheet - Page 139

• Manufacturer Part Number: MC68HC708XL36
• Description: HCMOS Microcontroller Unit
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

DMA Control
Register 2
29-dma_b
MOTOROLA
Address: $004E
DMA control register 2 can perform two functions:
SWI[7:0] — Software Initiate Bits
Use the following steps to generate a software-initiated DMA service
request:
Reset:
Read:
Write:
1. Enable a channel to perform a transfer by setting its TECx bit.
2. Assign the channel to a DMA transfer source by writing a binary
3. Set the SWIx bit that corresponds to the selected transfer source.
•
•
Each of these read/write bits corresponds to one of the eight DMA
transfer sources. (See
can initiate a DMA service request from the selected transfer source.
Freescale Semiconductor, Inc.
For More Information On This Product,
1 = DMA software transfer initiated
0 = DMA software transfer halted or not initiated
Initiate DMA transfers through software
Simulate DMA service requests for test purposes
(See
value from 000 to 111 to its DTS[2:0] bits. (See
Control Registers
The bit positions (0–7) of the SWIx bits correspond to the binary
values (000–111) that select the DMA transfer source. For
example, after selecting transfer source 100 (binary), set bit SWI4
to initiate the DMA service request.
SWI7
Bit 7
0
DMA Control Register 1
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Figure 19. DMA Control Register 2 (DC2)
SWI6
6
0
DMA
SWI5
Table 10
on page 140.)
5
0
SWI4
4
0
on page 142.) Setting an SWIx bit
on page 133.)
SWI3
3
0
SWI2
2
0
DMA Channel
MC68HC708XL36
SWI1
DMA Registers
1
0
SWI0
Bit 0
0
DMA
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