Freescale Semiconductor, Inc.
MOVE.W
#$0742,DMAINT1(A0)
* Initialize channel status reg.
* Clear the DONE, BES, BED, CONF and BRKP bits to allow channel to startup.
MOVE.B
#$7C,DMACSR1(A0)
* Initialize function code reg.
* DMA space, supervisor data space for source and destination.
MOVE.B
#$DD,DMAFCR1(A0)
* Initialize source operand address
* Source address is equal to $6000.
MOVE.L
SARADD,DMASAR1(A0)
* Initialize destination operand address
* Destination address is equal to $8000.
MOVE.L
DARADD,DMADAR1(A0)
* Initialize the byte transfer count register
* The number of bytes to be transferred is $64 or 50 words
MOVE.L
NUMBYTE,DMABTC1(A0)
* Channel control reg. init. and Start DMA transfers
* No interrupts are enabled, destination (write) cycle.
* Source address is not incremented. Increment the destination address.
* Source size is word, destination size is word. REQ is internal.
* 100% of bus bandwidth, dual-address transfers, start the DMA transfers.
MOVE.W
#$068D,DMACCR1(A0)
***************************************************************************
END
***************************************************************************
Example 4: Cycle Steal Request Generation, Dual-Address Transfers.
***************************************************************************
* MC68340 basic DMA channel register initialization example code.
* This code is used to initialize the 68340's internal DMA channel
* registers, providing basic functions for operation.
* The code sets up channel 1 for external cycle steal request generation,
* dual-address transfers. DMA 16-bit wide data from an odd address to an
* even address. Control signals are asserted on the DMA read cycle.
***************************************************************************
***************************************************************************
* SIM40 equates
***************************************************************************
MBAR
EQU $0003FF00 Address of SIM40 Module Base Address Reg.
MODBASE EQU $FFFFF000 SIM40 MBAR address value
MOTOROLA
MC68340 USER’S MANUAL
6- 43
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