MC68HC08XL36 Datasheet, PDF (116/362 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

DMA
Freescale Semiconductor, Inc.
The following procedure shows how to program a DMA transfer on a
selected channel:
1. In DMA control register 1 (DC1), disable the channel by clearing
the TECx bit. (See DMA Control Register 1 on page 129.)
2. In the source address registers (DxSH and DxSL), write the
source base address. (See DMA Source Address Registers on
page 137.)
3. In the destination address registers (DxDH and DxDL), write the
destination base address. (See DMA Destination Address
Registers on page 138.)
4. In the DMA channel x control register (DxC), make the following
selections (see DMA Channel Control Registers on page 135):
a. Select increment, decrement, or remain static for the source
and destination addresses by writing to the source/destination
address control bits, SDC3–SDC0.
b. Select 8-bit or 16-bit data by writing to the byte/word control
bit, BWC.
c. Assign a DMA channel to the DMA transfer source input by
writing to the DMA transfer source bits, DTS2–DTS0.
5. In the channel x DMA block length register (DxBL), write the
number of bytes to transfer. (See DMA Block Length Registers on
page 139.) For word transfers, the block length number is two
times the number of words.
6. In the DMA status and control register (DSC), make the following
selections (see DMA Status and Control Register on page 131):
a. Enable or disable looping of the source and destination
addresses by writing to the loop enable bit, Lx.
b. Select DMA service request/CPU interrupt request priority by
writing to the DMA priority bit, DMAP.
c. Enable or disable DMA transfers during wait mode by writing
to the DMA wait enable bit, DMAWE.
MC68HC08XL36
116
Direct Memory Access Module (DMA)
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10-dma_b
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