ST2202A
19.2 DMA Programming Flow
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DMRꢀ:=ꢀDMAꢀMemoryꢀbankꢀregister
(DMSH,L)ꢀ:=ꢀDMAꢀSourceꢀaddress
(DMDH,L)ꢀ:=ꢀDMAꢀDestinationꢀaddress
DCNTHꢀ:=ꢀNumberꢀofꢀBytes
DCNTLꢀ:=ꢀNumberꢀofꢀBytes
DMAꢀStart
CPUꢀhold
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FIGURE 19-2 DMA Programming Flow
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19.3 Example Program 1:
Thisꢀprogramꢀfillsꢀ“00”ꢀtoꢀaddressꢀ$1000~$12FF.ꢀ
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ꢀ ꢀ ꢀ
STZꢀ
STZꢀ
LDAꢀ
STAꢀ
STAꢀ
LDAꢀ
STAꢀ
LDAꢀ
STAꢀ
LDAꢀ
STAꢀ
$1000ꢀ
<DMSLꢀ
#$10ꢀ
<DMSHꢀ
<DMDHꢀ
#$01ꢀ
<DMDLꢀ
#$02ꢀ
<DCNTHꢀ
#$FEꢀ
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ꢀ
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;;ꢀ“00”ꢀtoꢀ$1000ꢀ
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;;ꢀsourceꢀ=ꢀ$1000ꢀ
;;ꢀdestinationꢀ=ꢀ$1001ꢀ
<DCNTLꢀ
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;;ꢀmoveꢀ$2FFꢀbytesꢀ
ꢀ ꢀ ꢀ :ꢀ
ꢀ ꢀ ꢀ :ꢀ
Verꢀ2.5ꢀ
58
/75
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9/16/2008ꢀ