On Fri, 6 Nov 2009, Tornado wrote: > Im working with a router WRT320N with broadcom 4716 processor, mips32 > 74k core. I have no information to speak of on this board, I am used to > an ir length of 5 or 8 for broadcom CPU's, Openocd complains about 5 or > 8, with an error a bit 8. I have tried detection with a few other > applications, and they both tell me IR length is 32. > > the IDCODE seems to be detected correctly, but the IMPCODE is always > different, as a matter of fact, if I change the define for IDCODE to > IMPCODE, I still get IDCODE, its as if the board is locked, and will > only give up IDCODE. > > Q. How can I correctly identify the IR length, etc ? knowing I have no > access to documentation.
I don't know the exact commands to do this in OpenOCD (hopefully others can fill in the details), but it is theoretically possible. The JTAG standard specifies that the bottom 2 bits of IR are "01" when it is captured, so to work out the IR lengths of the entire chain, step the JTAG TAP to IRSHIFT, via IRCAPTURE, and then clock a long string of 1s into TDI. You should get a string of 1s back, preceded by images of the IRs in the chain, each ending in 01. For example, if you had a chain with an IR length of 4 followed by an IR length of 6, you should see: 11111111111110000010001 coming back, with right-most digits coming out of TDO first. You may need a tool other than OpenOCD to do this scan, and then plug in the irlength values one you've worked them out. _______________________________________________ Openocd-development mailing list Openocd-development@lists.berlios.de https://lists.berlios.de/mailman/listinfo/openocd-development
