#7 Increase flash programming speed

[millerton]

Hello,

is there a way to increase the programming speed of the spi flash used to configure the fpga?
I mean not when loading from the flash but during writing the content to the flash (after bscan.bit has been loaded to the fpga and the fpga acts JTAG->SPI converter)
I am using the Digilent Arty board (XC7A35T fpga and N25Q flash).

I looked into the bscan.bit source and think that the DRCK output of the BSCANE2 instance is the clock that drives the spi bus, but DRCK is the gated output of the JTAGs TCK clock pin, which is unconnected.
Does it use a fixed internal oscillator? Or is it configured via JTAG instructions?

Any information on how to increase the spi clock speed would be great. Because right now it takes me 90s to program the flash on the Arty board.

Regards,
Michael

[Uwe Bonnes]

Did you check to see if speed is limited by Jtag/Algorithm speed and not by pure flash write speed?

To increase JTAG speed, use a FT2x32H device that can do JTAG at 30 Mhz versus only 3 MHz on the other FTDI devices Be sure you have tolerable ringing if the FT2x32H is connected via cable. If algorithm need speedup, look at how OPENOCD handles Flash write via BSCAN_SPI.

At the moment, xc3sprog is in maintainance mode and I will apply sensible patches but will not do any own work.