Intel LPCI-7200S manual OREQ & OACK for Digital Output, Operation Theory

Digital Input DATA

21

IN_REQ

IN_ACK

PC's Main Memory

			Latch Digital Input
			or Digital Output
	4	3
Bus mastering	Digital Input FIFO
DMA data Transfer

5

O_REQ & O_ACK for Digital Output

1.Digital Output Data is moved from PC memory to FIFO of PCI-7200 by using DMA data mastering data transfer.

2.Move output data from FIFO to digital output circuit.

3.Output data is ready.

4.An O_REQ signal is generated and sent to outside device.

5.After an O_ACK is captured, steps 2-5 will be repeated.

**If the FIFO is not full, the output data is moved form PC‘s main memory to FIFO automatically.

Digital Output DATA

O_REQ

O_ACK

PC's Main Memory

43

Move Data to

Digital Output

5	2
Bus mastering
DMA data TransferDigital Output FIFO

1

32 • Operation Theory