What are the various buffers in DB-mode and how are they related to DMA for the 653x?

[rklein]

I have to do dubble buffer input with the PCI-6534 board (OS Windows 2000). What is the relationship between the two buffers passed to DIG_Block_In and DIG_DB_Transfer? How is the DMA actually happening?

[Filipe A.]

Hello;

The DIG_Block_in is starting the transfer in between the onboard FIFO and the PC buffer, and the DIG_DB_Transfer deals with the transfer of data in between the PC buffer and the application software buffer. So, the DMA controller is being started by the first function and the second one is responsable for passing the data to the application software array.
Hope this helps.
Filipe

[rklein]

Do I understand it right? DIG_Block_In starts the DMA transfer to the buffer passed in DIG_Block_In and the board writes the data from the FIFO cyclicaly into this buffer using DMA. DIG_DB_Transfer copies the "safe" half of this buffer to the buffer passed in DIG_DB_Transfer. Thus, it operates only in the PC's memory and does not interfere with the 653x board or the DMA controler. Right?