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Hello,
so. I have a pretty complex question. I know that it will be hard to answer without physically seeing my hardware setup that I have in front of me, so i will try and provide some schematic screenshots and describe what I am trying to do, and THEN I will describe what is going wrong, and THEN i will ask my question. Please follow along and reach back out with questions. I am in DESPRITE need of help.
1) WHAT I AM TRYING TO DO
-I recently embedded my own custom C2000 TMS320F28384D controller myself, following the same design principles from the launchpad PCBs, i have followed the datasheet to a T about capacitors, voltage levels, resistors, etc. Essentially my board is a totally empty breakout for the processor. I broke out almost all of the pins, verified them a ton of times etc. My specific package for the processor is the BGA with like 337 pins about?. Below, i have attached my schematic. Under my schematic I will tell you the steps I have taken from the schematic design until now, where the board is on my desk.
I will also attach the design as the altium sch and brd files for your reference.F28384DZWTSR_testBoard -simplier.zip
-okay so, since creating these design files i have done the following.
-manufactured and built the board via Macrofab. I did not do any soldering myself, i am confident the BGA is on there correctly. They did electrical testing, so i think electrically speaking, the circuit is in good shape.
-Checked for shorts manually with a DMM, it all looks good.
-made sure that the power converters were working. I am successfully getting the 3.3V and 1.2V nets just like the datasheet needs.
-Connected up power, and turned on the power switch, power LED lit up as expected.
-wired up a XDS110 debug probe to the jtag header, i had to go through a breadboard to do so because I accidentally broke the jtag stuff out in a line and not in two rows as is the 14 pin header of the XDS programmer.
-verified this circuit works by touching the TDO and TDI lines in a loop NOT connected to my board, and running a "test connection" in CCS. The programmer is working when it just loops back to itself.
2) WHATS GOING WRONG:
-Whenever I connect in my jtag TDO and TDI lines to TDO and TDI respectively, (i am following the TMS320's datasheet on how to connect a 14 pin jtag programmer), the JTAG test connection fails, and i get this message:
The value is '-233' (0xffffff17).
The title is 'SC_ERR_PATH_BROKEN'.
The explanation is:
The JTAG IR and DR scan-paths cannot circulate bits, they may be broken.
An attempt to scan the JTAG scan-path has failed.
The target's JTAG scan-path appears to be broken
with a stuck-at-ones or stuck-at-zero fault.
-I get the SAME error if i just leave TDO and TDI unconnected from the XDS110. This tells me the processor is not booting up to where it should be for some reason. I have never brought a C2000 processor online for the firs time besides on a launchpad, so i don't really know how to get the device to boot up right. I know other controllers like STM32s have a boot0 pin you have to tie low the first time you program, but i am not able to find something like this in the datasheet.
3) MY QUESTIN:
- Basically, my question amounts to this: What is the correct order of steps for first time programming on a c2000 chip? If I need to add switches to my circuit i can! I have broken out about EVERY pin from the BGA, so i WILL be able to make circuit changes if needed. Please help me figure this out. I have included photos of the schmeatic, and if those are not enough, I also zipped up my whole altium project and attached it. I can provide any further photos of anything if needed. I really need to know how to program this chip for the first time.
-Oh ALSO, I made a new CCS project for this thing, and specifically selected it as the target. Made it an empty main.c program, and then added a config file to select the XDS110 probe as the programmer. The step I am stuck on is clicking "test connection" in the .ccxml config file. Oh and here is a screenshot of my JTAG setup on CCS.
-I have tried adjusting the JTAG TCLK frequency to a lot of values between 100Khz and 20 MHz, and that change dose not make a difference to my test results. I am very confident I am just missing something hardware wise in getting the processor to boot up correctly the first time.
If this would require a video or auido call to help me, I am happy to zoom or whatever is best. Just send me a email at silas.perry@whisperaero.com.
thanks!!!!
Hi,
If you have access to an oscilloscope, could you try probing TDO (yellow), TMS (purple), TCK (blue), and TRST (green) as shown below. The screenshot below was captured using the XDS100, and it was a single-capture triggered on the falling edge of TMS. Could you try doing the same and see if your probed signals look the same? I'm assuming from your error message that you won't see anything on TDO, but I want to make sure.
What do you see on the XRSn pin when the device is powered on? On an unprogrammed device, you should be seeing a reset every ~50ms due to the watchdog.
Your JTAG circuit looks correct in the schematic, and there are no special steps for first time programming. I would be curious to see scope captures on the power rails to make sure the voltages look good.
Best Regards,
Ben Collier
Hello Ben.
Thanks for your reply. After reading your message, i decided a good first scope measurement to take would be the power ground rails as well as the XRSn pin. I have attached the following below. First is the 3.3v net, next is the 1.2V net, and third is the XRSn pin.
I am nervous about what I am seeing on the XRSn pin. Instead of the pulses you described, it looks like it is just getting tied high to 3.3V all the time. So the forth image is my circuitry for that specific pin, which is also viewable in the above screenshots but i included it here to highlight and zoom in on it.
Does it look like i connected the XRSn pin wrong in my schematic? it is tied to 3.3V through a resistor as seen in the 4th figure below. Please see below.
figure 1 - 3.3v net measured on power rail
figure 2 - 1.2V net measured on power rail
Figure 3 - XRSn pin measured at point indicated in figure 4
figure 4 - XRSn circuit, also shows where scope was to measure.
Please get back to me as soon as possible, I apricate your time.
thanks,
-Silas Perry
hello.
Yes i can try replacing R3 with any value. Below is a scope shot of TDO when the probe is plugged into my board, during a "test connection" from CCS.
I have NOT replaced the resistor yet, but i will do so now.
Here is the screenshot:
Here is another screenshot of all JTAG lines on logic analyzer, before i change the resistor value of R3
again before I change R3 i logic analyzed the XRSn pin, and i am getting the following waveforms. the second one is a zoom in on the falling edge of each pulse. I don't really know what I am seeing here.
The width of each pule is 40us, and the width between each pulse is 2.38ms.
Hello one last time.
I did not have a 10k, but I actually had the wrong resistor value there at the first try. I changed it to be 2.2k like it should have been. I am now seeing the following waveform when trying to test:
THis might also help.
When i completely unplug the probe from the circuit, the following can be seen on the logic analyzer.
Hello, I have followed the following circuit exactly.
The 8 pin header has the pins on the left side exposed, and i am using the 20-14 pin connector of the debug probe to jump the wires from that over to a breadboard where they meet the wires of the controller from that 8 pin header.
I have lowered the clock on jtag to only 100kHz, so there should be no issue with using the breadboard as an intermediate between the processor and the debug probe. I have double and triple checked the connections so many times on teh breadboard between the probe and processor, i know it is correct to the above picture.
Again, the point where the processor stops its pulses is when i plug the power and ground lines in from the 8 pin header to the breadboard so the probe is connected and able to sense the power rail of the controller.
