Hello folks, I just received my Udoo Quad and I must say it's a really great device. For my project I want to use the SAM3 in bare metal mode so I need access to the JTAG. From the schematics, I learned that the JTAGs of the i.MX and the SAM3 are partly wired together on J17A1. I could remove R1103 so that the TCK signal is just routed to the SAM3 and R166 so that the reset of the reset from the JTAG interface does not reset the whole system. However I wonder if this is enough to keep the i.MX running while debugging the SAM3 since the TDI and TMS signals still are routed to both processors. Especially the TMS since this is the SWDIO signal on Cortex-Ms. Has anybody tried this? Except from the schematics, I couldn't find documentation about this.
Hi insanelygreat, i'm also interested to use the jtag for the cortex m3, have you any success with it ? Please let us know the procedure. Thanks in advance.
Hi, we are going to publish informations and documentation as soon as possible. Thank you for your question It's very helpful for us to understand and solve all the UDOOs issues.
Hello, I just tried it and it is exactly as I thought. I was successful in reading out the SAM while keeping the i.MX running by unsoldering R1103 and connecting a Segger J-Link. If you don't unsolder R1103, the i.MX crashes. I would like to share my experiences with bare metal usage of the SAM and write some documentation. What ist the best place to do so?
Nice idea, udoo team a solution ? I already have a jlink probe, can you share your jtag pinout please ?
We used Jtag for debugging the i.mx6 at the development stage but not with the SAM3X. You need to mount the J17A1 to make it work. You can find more info here: http://udoo.org/download/files/schemati ... matics.pdf http://udoo.org/download/files/schemati ... _rev_d.pdf
Sure. The hardest part of it is getting J17A1 in place because you have to clear the holes of solder first. After that, it's the standard ARM SWD pinout. (which is a low pin count interface found on all ARM Cortex-Ms. Does the same thing like JTAG but with less pins) UDOO J17A1 --> J-Link Pin 1 (VCC) --> Pin 1 Pin 2 (GND) --> Pin 4 (or any other of the J-Link GND pins) Pin 4 (TCK) --> Pin 9 Pin 7 (TMS) --> Pin 7
