ADLINK PCI-7200 - Manual (Page 49)

Operation Theory 37
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