Here's an issue with my customer:
We are using the TMS320VC5510 with a PLX Net2272 which connects to our EMIF parallel bus. We would like to allow it to access DMA reads and writes from the DSP. According to one PLX’s appnotes for an interconnection of the Net2272 and the TMS320DM642; the NET2272 has a DMA REQ pin which connects to a second interrupt line (INT 5 on the DM642) and a DMA ACK which they are using a logic gate circuit to drive as a combination of A22 and chipselect where as a read or a write to the USB chipselect with A22 high will toggle the DMA ACK pin.
My questions are the following:
1) Can our DSP respond to an external DMA request like the TMS320DM642?
a. Is this just a normal interrupt which the CPU then sets up the DMA read or write?
2) The chip selects in our DSP are tied to a specific memory address. Each CE can access 4MB wide. So should we hook up the MSB of the chipselect region to the DMA ACK logic or the next greatest address bit which is connected to the USB chip. (USB chip has 5 address bits with a 1 bit shift for 16 bit access so it is A5:A1 so should I use A6?
Thanks