Hi Matt, ok I made some progress. Being a hardware engineer I decided to take a look at the status of the JTAG pins when the XDS200 is trying to connect. In the scope plot below, C1 (Yellow) is TMS, C2 (Red) is TDI, C3 (Blue) is TDO and C4 (Green) is TCK. This is the first activity on the JTAG port when I try to connect with the target configuration tool. We get activity on TCK and TDI but nothing on TMS or TDO. I'm not sure if this is expected or not but I read the guide you included and noticed that there is an ability to connect to this part using only two pin JTAG:- I changed to the cJTAG (1149.7) 2-pin advanced mode with the setting as shown above and..... this allows me to connect to the device, program flash and read debug values. I went down this route out of curiosity and after seeing some of the JTAG signals not being active with the normal four wire approach. The questions I have are:- 1) Any idea what might be causing this? The board has been happily running with the default four wire JTAG for months and I don't use any of the GPIO's which are multiplexed with the JTAG pins 2) Is this an acceptable way to program the device? I've never used it before and only stumbled on it by a bit of luck. Thanks, Iain
↧