Laurent Gauch wrote: > That's a real good point for Rowley Crossworks > http://www.rowley.co.uk/arm/index.htm and Amontec JTAGkey Series > http://www.amontec.com . Note, with the use of Amontec JTAGkey-2 based > on high-speed USB, Rowley Crossworks becomes still a lot faster since > the USB latency go form 1ms to 125us.
Any real solution just has to give up trying to run this from the PC. It's stupid. I think some dongles do more or less of it already. FT2232 obviously does not do it at all, whether full or high speed. The USB-Blaster CPLD seems to be slightly more clever, but is not quite fully utilized. A PC is USELESS for any kind of bitbanging or the like (MPSSE in crap FTDI chips counts just the same!) - there are *at least* THREE bus masters between CPU and IO pin, and you want it to be fast? Come on.. Anything sensible will just use a higher level protocol and a more intelligent hardware. Life will be good. The Versaloon is the only sensible dongle at reasonable cost I have seen so far. Simple no-nonsense design and great support from Simon. I recommend it to everyone. A bit of integration with OpenOCD may still be missing but that can not be too difficult. Best of all - even the firmware for the adapter itself is open source! > For the OpenOCD, we know there are some optimizations do be done on > the software to accelerate the USB JTAG cable. The bottleneck is stupid adapters. > Removing the effect of the USB latency is a real challenge, What's the problem? //Peter _______________________________________________ Openocd-development mailing list Openocd-development@lists.berlios.de https://lists.berlios.de/mailman/listinfo/openocd-development
