Harry, Yes, that was the basic idea behind what I wanted to do. I don't even care if I can bypass a specific unit, I'd be happy to program them all at once in a huge chain. Roughly: scan in the first word for all devices in a huge string, program that to flash, repeat with second word,... That way, each device could have a unique program and/or EEPROM loaded but they could all be programmed from only one JTAG connector.
The "simple" thing I need is the software. :-) I just looked at the link Chris posted. (see http://www-s.ti.com/sc/psheets/slaa149/slaa149.pdf) I may be able to write my own software for this. Hmmm... I was hoping I could get someone (Steve Underwood?) to answer and say it is already supported with the current tools or that it would be a trivial change and would be released soon. Steve - could you please tell me if it is at least possible or not with the public documents from above? (no NDA) If "N" deviced are daisy chained together, can they be programmed in one big chain? Does TDO always reflect a copy of TDI delayed by X TCK cycles? The gang programmer will be an acceptable alternative although not nearly as nice for these 2 reasons: 1) All devices must be programmed with the same data 2) Only supports up to 8 devices at a time. - Dan Miner > From: Harry Lemmens > Sent: Wednesday, January 28, 2004 7:58 PM > > Thanks for that Chris. > > The reason I asked is that (I think) by using the BDSL > "Bypass" instruction, a device effectively be frozen out of > a system during boundary scan. The data passes from the TDI > pin to the TDO pin, but does not access internal JTAG > "functions. > > So by daisy chaining the TDO/TDI pins on multiple devices, > and paralleling TMS and TCK to all the devices, it would have > been possible to configure a string of MSP's (The last device > in the chain would be the first device requiring configuration.)
