Intel cPCI-7200 - Manual (Page 40)

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• Operation Theory
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.
Move Data to
Digital Output FIFO
Bus mastering
DMA data Transfer
PC's Main
Memory
2
4
3
1
Digital Output DATA
5
Digital Output
O_REQ
O_ACK
Latch Digital Input
or Digital Output
Digital Input FIFO Bus mastering
DMA data Transfer
PC's Main Memory
2
4
3
1
Digital Input DATA
5
IN_REQ
IN_ACK