Am Mittwoch 25 Mai 2011, 22:56:48 schrieb José Silva: > On 25-05-2011 21:18, Michael Walle wrote: > > Am Mittwoch 25 Mai 2011, 18:11:42 schrieb José Silva: > >> On 25-05-2011 16:53, Andrew Dyer wrote: > >> > >> Andrew, thank you for the tip. > >> > >>> ejtag is just for mips cores. It doesn't work on ARM. > >> > >> jtag> help initbus > >> > >> Doesn't refer any ARM appropriate bus. What would you recommend then? > > > > mh either writing your own bus driver or using the prototype driver if > > every pin your flash is connected, can be controlled via boundary scan. > > > > the latter can be very slow! > > Michael, thank you for replying, > > Although I work in electronics, hard and soft (or firm, better said) for > more than 40 years (I saw the birth of the first microprocessor, the > Intel 4004), I must confess that I know almost nothing of jtag and > boundary scan. http://en.wikipedia.org/wiki/Boundary_scan in short, you are able to drive the physical pins directly (or read the logical value, eg treat it as an input pin). not all pins are suitable for boundary scan testing (eg. the jtag pins themselves.. or power etc)
> That said, this thing is driving me nuts; I have also tried openocd with > no results; I can't get it to halt. does openocd recognize the device correctly? Eg sth like that: Info : JTAG tap: feroceon.cpu tap/device found: 0x20a023d3 (mfg: 0x1e9, part: 0x0a02, ver: 0x2) Info : Embedded ICE version 0 Then you are connected to the ARM debug port and boundary scan isn't possible (that is the prototype driver can't work). > One thing I can't understand, for instance, is why urjtag detects a chip > with irlen of 8 when I know the core cpu is an arm926ejs with an irlen of > 4. you may be on the wrong chain. eg. i have a marvell 88f6281, which also has an arm 926ejs core, which has two jtag TMS pins. one for the internal arm debug port (for software debugging) and one for the boundary scan 'mode'. > > So, I guess you won't be surprised if I confess that I don't know what > you mean by "if every pin your flash is connected, can be controlled via > boundary scan" see above That all being said, ARM just provides the core itself, there are many actual processors which are using an arm 926ejs core. you should try to find out which processor is stuffed on your board. btw i see that there is an arm9tdmi bus driver, which may be working for you. but as mike already said, you need the data files/bsdl files for your processor first. -- Michael ------------------------------------------------------------------------------ vRanger cuts backup time in half-while increasing security. With the market-leading solution for virtual backup and recovery, you get blazing-fast, flexible, and affordable data protection. Download your free trial now. http://p.sf.net/sfu/quest-d2dcopy1 _______________________________________________ UrJTAG-development mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/urjtag-development
