Dma Processing Procedure - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 3 INTERRUPT
3.6.3

DMA Processing Procedure

If an interrupt request is generated by a peripheral resource (I/O) and the
corresponding DMA enable register (DER) has a setting of DMA start, then a DMA
transfer is performed. If a data transfer ends at the specified count, an interrupt
request is output to the interrupt controller.
I DMA processing procedure
Figure 3.6-7 "DMA processing procedure" shows a simple DMA processing procedure
DERx: DMA enable register
DSRx: DMA status register
78
Figure 3.6-7 DMA processing procedure
Software processing
Start
Setting up of system stack area
Definition of DMA descriptor
Initial definition of peripheral
function
Definition of interrupt control
register (ICR)
Initial definition of DMA
controller
Setting up of ILM and I in PS
Execution of user program
DMA transfer end
Clearing of peripheral
interrupt
Clearing of DSR register
by software
RETI
Hardware processing
Clearing of peripheral interrupt
(Interrupt request) and (DER: ENx = 1)
DMA data transfer
Evaluation
of end request from count-
out event or resource
YES
DSRx="1"
NO