A826_ad_dma_start, 3 a826_ad_dma_start – Omega Engineering OME-A826PG User Manual
Page 52
OME-A-826PG Software Manual [Win 95/98/NT]
3.6.3 A826_AD_DMA_Start
z
Description:
This subroutine will allocate a DMA buffer in the system area, and
programming the gain code and sampling rate. then starting the DMA transfer for
a specific A/D channel.
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Syntax:
WORD A826_AD_DMA_Start(WORD Ch, WORD Gain, WORD c1, Word c2,
int Count, WORD wPassOut[ ] )
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Parameter:
Ch :
[
Input
] the A/D channel.
Gain :
[
Input
] the Gain code
c1,c2
: [
Input
] the DMA sampling rate is 2M/(c1*c2)
Count
:
[
Input
] the desired A/D entries count for DMA transfer.
wPassOut[] :
[
Output
] the debug information.
wPassOut[0] : [
Output
] 0: successful in starting DMA transfer.
others: fail in starting DMA transfer.
wPassOut[1] : [
Output
] system DMA buffer ID.
wPassOut[2] : [
Output
] the I/O port base address.
wPassOut[3] : [
Output
] the IRQ level for DMA.
wPassOut[4] : [
Output
] the DMA channel no.
wPassOut[5] : [
Output
] reserved.
wPassOut[6] : [
Output
] reserved.
wPassOut[7] : [
Output
] reserved.
wPassOut[8] : [
Output
] the last 16 bits of physical address
for DMA buffer in system area.
wPassOut[9] : [
Output
] the first 16 bits of physical address
for DMA buffer in system area.
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Return Value:
NoError
: successful
DmaStartError
: failure
Date: Aug-15-2000 Ver: 2.2 Page 50