On Fri, Jun 17, 2011 at 1:07 PM, Uwe Bonnes
<bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>>>>>> "Caleb" == Caleb Kemere <ckemere@xxxxxxxxx> writes:
>
> Caleb> I've noticed previous threads where folks have used the
> Caleb> synchronous FIFO mode of the FT2232H and gotten quite reasonable
> Caleb> sustained transfer rates (15 MB/s). I'm struggling to get 6.5
> Caleb> MB/s (without the buffer on the chip filling up). Is this an
> Caleb> issue of the asynchronous FIFO mode, or am I somehow not pulling
> Caleb> data off on the PC fast enough?
>
> What direction is the transfer? Device to PC or PC to device?
Device to PC. (The device is a Spartan, I forget what kind.)
> I only have experience with synchronous read at high rate. Is your hardware
> fast
> enough? Lookin at the datasheet, I see 80 Nanoseconds needed for each vyte by
> the FT232 in FT245 Style Asynchronous FIFO Interface Mode. So if your
> hardware adds another 80 ns, you will loose.
We've set up the FPGA to stop sending if the FT2232H ever signals that
its buffer is full. So that's what's happening.
> Otherwise, how do you read on the PC side? Do yo do asynchronous reads like
> in libftdi-1.0/src/ftdi_stream.c?
I have been doing a loop of ftdi_read_data(). I'm just starting to
play around with libftdi-1.0.
thanks!
– caleb
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