Cypress FM4 Series - DMAC Operation and Control Procedure for Software Transfer

CHAPTER 10: DMAC
470 FM4 Peripheral Manual, Doc. No. 002-04856 Rev. *E
4.2 DMAC Operation and Control Procedure for Software Transfer
This section explains DMAC operation and control procedure for software transfer.
Figure 4-1 Transitional Diagram of Software DMA Transfer State
Figure 4-1 shows a transitional diagram of the states of the channel to be controlled for software transfer.
The numbers next to the transitional lines in the figure correspond to the numbers which appear in the
following control procedures. The solid transitional lines indicate transitions of state instructed by CPU,
while the broken transitional lines indicate transitions of state due to DMAC operation.
Transition by CPU
Transition by DMAC
2
4
,
5
3
Disable
DE=0 or EB=0 or
DH!=0000 or PB=1
initial : SS=000
after stop : SS=code
Transfer
DE=1 EB=1
DH=0000 PB=0
SS=000
Pause
DE=1 EB=1
DH!=0000 or PB=1
SS=111
6
6
1
,
7
,
1
1
8
9
1
0
Reset