Joerg Reisenweber wrote: > In fact both are programmable to support a variety of different modes, IIRC.
Yup. What I meant is the configuration we're using. We could of course change modes on the fly, but that may get a wee bit confusing ;-) > Seen this, a plain bug, nothing else (or maybe the selfdestruct feature ;-) Good :) > Both ports are identical. Only in UART mode that is the usual mode for > channel B on debugboard_v3. No? They're subtly different. A quick look reveals the following differences: - MPSSE is only available on channel A - they have different roles in MCU Host Bus Emulation Mode (not that we'd care) - if both are in Fast Opto-Isolated Serial Mode, only channel B does I/O (again, not relevant for us) > Hey what's wrong with 'muxing' JTAG? Design risk. More moving parts -> higher risk. > I suggested a jumper block to have 6400, or 43, or 430 + 6400, depending > on jumper setting. You could also use it to directly connect to any one > of the 2 chains. Hmm, for GTA04v0 that may actually be a nice choice, given that we don't care about space anyway. Jumpers are a sufficiently basic technology that I feel I can trust it ;-) Much safer than a JTAG mux. > Hmm, I don't see this: Use JTAG to disable, to prepare to use JTAG? The idea would be to catch the CPU/MPU with JTAG before it gets a chance to do bad things to I2C. - Werner
