On 2007-11-08, Chris Liechti <[email protected]> wrote: > Grant Edwards schrieb: >> Can anybody confirm that the JTAG applications work when there >> are other devices besides the MSP430 in the TJAG chain? > > i can't. ;-)
I had to give up on it. TI's JTAG implementation is non-compliant but can be made to work (electrically) as long as it's the first device in the chain. I was able to get various AVR tools to talk to the the AVR (the second device in the chain). Somebody who's seen the internals of the TI libraries assured me that they don't know how to deal with any other devices in the chain. > the mspgcc jtag library doesn't do that currently. but maybe > you're able to find out what needs to be changed. For the AVR tools you have to tell them how many devices are located before/after the target device and the total number of bits located before/after the target device. > the MSP403 JTAG allows to source the MCLK from TDI in one > certain state of the JTAG machinery. this probably explains > why the MSP430 must be the first device in the chain. the > slau149 application note has some details. Right. >> According the the TI datasheets, it's supposed to work as long >> as the MSP430 is the first device in the chain (which it is), >> but I can't seem to talk to the MSP430. > > with msp430-jtag --backend=mspggc, did you try to specify a > number of -D options? it should report quite detailed where it > fails? No, and I'm afraid I can't really spend any more time fighting with TI's broken JTAG stuff. I gave up and allocated a couple extra pins on the debug header for the board in question so that the two TAP controllers aren't in series. I've been told that all of TI's JTAG implementations are messed up. The OMAP parts that contain an ARM core and a TI DSP core have _two_ jtag interfaces: one for the ARM and one for the TI part. OTOH, I've corresponded with people that have been able to mix-and-match devices from a half-dozen other vendors in a JTAG chain with no problems. TI seems to uniquely unwilling/unable to properly implement. -- Grant
