Hi,
I´m using a N25Q128..3E to store a bitstream configuration for an FPGA. To program the flash I´m using an ftdi2232H chip. I have two ways how to program the flash (with the same ftdi chip!): Via the JTAG and the FPGA (which first loads a JTAG to SPI converter core to do so) or directly via SPI.
I prefer the last way as it is with less possible error points and I suppose that it should be faster.
My problem: Programming the flash directly via SPI is much slower than the indirect way through JTAG and the FPGA. I think that it does not has to do with the SPI clock frequency as it is even slower in indirect case. But I can observe a significant difference in the Idle time between two SPI sequences/packages.
You can see that at attached screenshots. The idle time (red arrows) is 2 - 4 times longer in direct case (below) than in the indirect (above) (as there are about 16000 SPI sequences it really does matter).
1. I couldn't find any flashrom parameters to change idle time. Is there any? 2. When looking at the source code I found the function call 'ftdi_set_latency_timer' but can´t find the function definition. Does it has to do with the idle time? 3. Which function should I touch to change idle time if there is any to do so? 4. Any other advice about how to change the idle time?
Regards,
Simon
-
Buhrow, Simon