Hi
I achieved only 550kBps, but I didn't do any soft emulation or negociation. If your port is set to epp/ecp, there's a register in the ecp configurations that changes the mode of the port to ecp, epp or spp. If your port is set to epp in the bios, it should allways be so...
Ricardo
>
> > Yes, I have 2 commercial products using this. I get about 800 nS/byte
> > with a short
> > IEEE-1284 cable. Note that the PC EPP chips don't follow the IEEE-1284
> > standard,
> > they don't delay the strobes, but present them about the same time as
> > the data
> > port changes. So, you have to apply delays to the strobes in your device.
> > Then, you have to have the handshake signals bounce back through the cable
> > twice (once to tell the CPU data is available, then the request from the CPU
> > has to go away, then the remote device has to un-busy the bus.)
> > I don't use any overhead software, but map to the port and control it
> > directly
> > with inline assembler directives in the C code for x86 INB and OUTB
> > instructions.
>
> What are the products that you use? 800nsec/byte transfer rate is great
> and will solve all my problems. Currently I get about 10usec/byte as I am
> emulating the EPP protocol in SW. I have written a State-Machine in the
> FPGA for implementing the EPP protocol but have not done the
> EPP negotiation part. On the PC side acquisition software, all I did
> was to write a user-level program that made use of the libieee1284
> functions.
>
> I am hoping that after implementing the negotiation in the FPGA, the EPP
> protocol will run directly without having to emulate it in PC.
>
> My aim is to transfer 40KBytes/sec of data from FPGA to PC using parallel
> port.
>
> Thanks,-Yash
>
>
> > 1 Meg Byte/second is pretty ambitious, given the performance of the chips.
> > If you have long blocks of data to transfer (several K bytes in one
> > block) then
> > the DMA mode of transfer may go a little faster. I haven't done this,
> > as 20 bytes or
> > so at a time is the most I can do with my particular device.
> >
> > What is the rate of data transfer you are getting now? What method are
> > you using to access the parallel port?
> >
> > Jon