Hi Andreas, On 03/06/13 08:33, Andreas Fritiofson wrote: > I agree that it sounds like an SRST problem. I know that some versions > of the Olimex dongles suffers from a design fault causing the reset line > to be pulled down slightly (or even clamped) even when not asserted. > [...] Measure the SRST voltage and make sure it's > at Vdd level. Also check any other circuitry you may have connected to > the SRST pin. If you find a problem with the dongle, you may simply > disconnect the reset line since in many cases you can manage without it > (and the default is to not use it anyway).
I just had a crack at this again... my multimeter measures 3.3V on that pin with the dongle disconnected, 0.7V with it connected. I think the JTAG dongle is dragging the nRST (that's what it's marked as here; pin 15 on the standard ARM pinout) pin and holding everything in reset. I'll see what I can do about the ribbon. If need be, I'll cut the offending wire in the ribbon cable and wire in a toggle switch (so I can re-connect SRST if needed). Out of interest... is there some document that describes an OpenOCD-compatible protocol which I could implement on a MCU like a AVR to make a crude JTAG programmer over RS-232 or similar? That'd also help pull me out of a hole if this programmer goes completely on the fritz ... breadboarding a JTAG programmer with ATMega8L will be faster than ordering one online since I have the parts here. I know of the Bus pirate; and there's an AVR-based cousin, the "bus ninja" which I tried to get working but didn't have any luck with. I'd be curious to see if people have heard of others. Regards, -- Stuart Longland (aka Redhatter, VK4MSL) I haven't lost my mind... ...it's backed up on a tape somewhere. -- Stuart Longland (aka Redhatter, VK4MSL) I haven't lost my mind... ...it's backed up on a tape somewhere. ------------------------------------------------------------------------------ How ServiceNow helps IT people transform IT departments: 1. A cloud service to automate IT design, transition and operations 2. Dashboards that offer high-level views of enterprise services 3. A single system of record for all IT processes http://p.sf.net/sfu/servicenow-d2d-j _______________________________________________ OpenOCD-devel mailing list OpenOCD-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openocd-devel
