https://lists.berlios.de/pipermail/openocd-development/2009-August/009939.html
1. It can only be built with the FTD2XX driver. libftdi supports FT2232H/FT4232H
since version 0.16
2. A speed value of 0 is used as a RTCK request indicator. This clashes with the
valid clock division value 0 that provide the highest fixed clock frequency.
3. The ft2232_speed_div function return the maximum selectable frequency (30MHz)
when RTCK is activated. It should return 0.
4. The ft2232_khz function return ERROR_OK when RTCK is requested even for
devices lacking RTCK support. It should return ERROR_FAIL so the upper driver layers
can detect this and try to fallback to a fixed frequency.
5. FT2232H/FT4232H have a backward compatibility function that divide the clock
by 5 to get the same frequency range as FT2232D. There is no code that disable
this functionality. I can not find anything about if this is enabled or disabled by default.
I think it is safest to actively disable it.
git-svn-id: svn://svn.berlios.de/openocd/trunk@2591 b42882b7-edfa-0310-969c-e2dbd0fdcd60
a634b5d52e