TMS320F28335: Connection of F28335 MCU to the FT2232H mini module

Hi Francesco,

Thanks for reaching out. I am not sure what TDS is in Ayushi's comments, perhaps they are referring to TCK as that seems to be the missing JTAG signal. In any case, yes you would need to connect the JTAG pins of the MCU to the FTDI module, per the datasheet, which I have copied below.

The RX and TX connections are only needed if you require serial communication while debugging, which is most likely the case with the USB module. I'm not entirely sure about the firmware for the FTDI, but a similar post (https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/828250/tms320f28379d-tms320f28379d-emulation-using-ftdi-chip-ft2232h-usb-to-jtag-converter/3064699) confirms that you should model the EEPROM after XDS100v2. Please let me know if this answers your questions.

Regards,

Peter

Hello Peter,

thanks for the reply. I have connect the 5 pins TRST, TCK, TMS, TDI and TDO of the FT2232H minimodule to the JTAG connector header on the USB docking station board which is shown below. The version of the USB docking station is R3. Basically what I am trying to do is to bypass the FTDI module on the docking station and use the FTDI2232H minimodule to connect to the JTAG pins of the c2000 instead.

When I try to test the JTAG connection to the device with CCS I get error value -183 (below you can find the test report).

Also, the pin 5 on the JTAG connector of the docking station is 0 V. I am powering the docking station with 5 V coming from the FTDI minimodule and all leds on the docking station are correctly lit.

Any suggestions?

thanks

Fra

[Start: Texas Instruments XDS100v2 USB Debug Probe_0]

Execute the command:

%ccs_base%/common/uscif/dbgjtag -f %boarddatafile% -rv -o -F inform,logfile=yes -S pathlength -S integrity

[Result]

-----[Print the board config pathname(s)]------------------------------------

C:\Users\E0502116\AppData\Local\TEXASI~1\
CCS\ccs1020\0\0\BrdDat\testBoard.dat

-----[Print the reset-command software log-file]-----------------------------

This utility has selected a 100- or 510-class product.
This utility will load the adapter 'jioserdesusb.dll'.
The library build date was 'Jan 1 2021'.
The library build time was '11:25:57'.
The library package version is '9.3.0.00032'.
The library component version is '35.35.0.0'.
The controller does not use a programmable FPGA.
The controller has a version number of '4' (0x00000004).
The controller has an insertion length of '0' (0x00000000).
This utility will attempt to reset the controller.
This utility has successfully reset the controller.

-----[Print the reset-command hardware log-file]-----------------------------

The scan-path will be reset by toggling the JTAG TRST signal.
The controller is the FTDI FT2232 with USB interface.
The link from controller to target is direct (without cable).
The software is configured for FTDI FT2232 features.
The controller cannot monitor the value on the EMU[0] pin.
The controller cannot monitor the value on the EMU[1] pin.
The controller cannot control the timing on output pins.
The controller cannot control the timing on input pins.
The scan-path link-delay has been set to exactly '0' (0x0000).

-----[The log-file for the JTAG TCLK output generated from the PLL]----------

There is no hardware for programming the JTAG TCLK frequency.

-----[Measure the source and frequency of the final JTAG TCLKR input]--------

There is no hardware for measuring the JTAG TCLK frequency.

-----[Perform the standard path-length test on the JTAG IR and DR]-----------

This path-length test uses blocks of 64 32-bit words.

The JTAG IR instruction path-length was not recorded.

-----[Perform the Integrity scan-test on the JTAG IR]------------------------

This test will use blocks of 64 32-bit words.
This test will be applied just once.

Do a test using 0xFFFFFFFF.
Scan tests: 1, skipped: 0, failed: 0

-----[An error has occurred and this utility has aborted]--------------------

This error is generated by TI's USCIF driver or utilities.

The value is '-183' (0xffffff49).
The title is 'SC_ERR_CTL_CBL_BREAK_FAR'.

The explanation is:
The controller has detected a cable break far-from itself.
The user must connect the cable/pod to the target.

[End: Texas Instruments XDS100v2 USB Debug Probe_0]

Am I missing some connections? 

Hi Francesco,

By USB docking station, I assume you are referring to the docking station used with the controlCARD, correct? Can you verify the position of SW1 on the controlCARD? I believe this should be in the 'OFF' position if you want to use the external F2232.

Regards,

Peter

Yes, I am using the docking station with the f28335 control card. Yes, the switch SW1 is in the off position..

Hi Francesco,

Good, sounds like the controlCARD is configured properly. You mentioned that the 3V3 header on the JTAG connector is not powered. Can you check the other power headers on the docking station and see if they powered or not?

Regards,

Peter

Yes, all 3.3 V and 5 V header pins on the docking station are powered.

Hi Francesco,

See our JTAG debug guide (https://software-dl.ti.com/ccs/esd/documents/ccsv7_debugging_jtag_connectivity_issues.html#cable-break) specifically regarding the cable break far warning. It mentions connecting pin 5 to power through a 100 ohm current-limiting resistor. Can you implement this and see if that resolves your connection issue?

Regards,

Peter

Hello Peter, 

Unfortunately it is still not working, I have tried the to connect pin 5 with 100 ohm resistance but no change.

Maybe it is not possible to access the c2000 JTAG pins through the docking station unless you have a JTAG debugger probe?

thanks

Fra

Francesco,

From the below schematic of the base board, can you advise where the 5V is getting injected?

I assume it is at SW1 either 1 or 3(or even 2 so you don't need the switch). This should(and apparently is) generating the 3.3V for the whole board; this should also go to pin 5 of the JTAG header, not sure why we would see 0V.

You will also want to make sure that the FTDI on the base board is held in reset, else there will be contention on the JTAG, you can do this by populating Jumper J8 to tie down the FTDI RST-In signal.  Let me know if this has been done as well.

Best,

Matthew

Hello Matthew,

The 5 V supply is provided at pin 2 from the external FTDI module and pin 5 on the JTAG header on the docking station is grounded for some reason. However, pin 6 is at 3.3 V while it should be, according to the schematic, not connected instead. Any idea why?

I have put the jumper J8 but no success.

thanks

Fra  

Francesco,

You mention pin 6 is 3.3V, on your base board this pin is clipped off, correct? 

You are right that this is a no connect, it is a key pin to make sure the JTAG header is placed correctly.

Perhaps this is an error on our baseboard, but this has been in the market for so long without any reports of issues so I'm confused as well.

The function of pin 5 is just to let the emulator pod know that the target has power, if it is grounded then the emulator will never connect.  This is usually a different error than cable break though, it will say that target has no power.

Best,
Matthew

Just realized you said pin5 is grounded, and not floating(I was assuming a swap).  If that is true, then obviously don't short them together!  Sorry I missed that.  Let me check on my side.  At least swapping the pins is in the realm of something that could have happened, but if pin6 is 3.3 and pin5 is ground that doesn't seem like something that could have been easily missed in our design.  And again, this is a very mature board, so unless there was a manufacturing defect I would have thought this would have been brought to our attention before now.

Best,

Matthew

Hello Matthew,

While on the JTAG header schematic pin 6 is clipped off, on the actual board pin 9 is clipped off instead.

I thought that maybe the JTAG schematic was up side down since if you imagine to flip it then pin 6 is clipped off and pin 5 is 3.3 V. So then I tried to swap the JTAG signal wires accordingly but it is still not working.

We have no problem to connect to the board with a XDS100 debug probe on the JTAG connector header - it works fine and we can debug the c2000. We are just struggling to connect to the JTAG header through an external FTDI - we are developing our own control card with c2000 embedded on it and therefore our tests on the docking station are a preparation for the future work on the new control card.

thanks

Fra

If an external XDS100 debug probe, plugged into the 14-pin JTAG header works, then the clipped pin is 100% pin 6 from the JTAG schematic, and you should connect the external FTDI as such.

Do you see 3.3V on the pin adjacent to the clipped pin, i.e. this is pin 5 PD/3.3.

Keep in mind that pins 4/8/10/12 are all ground so that would also correlate to it being inverted(vs the pin1 marker on the PCB).

There are also 2 types of XDS100 debug probes, a V1 and a V2.  Have you tried the external FTDI based emulator with either V1 or V2 to see if one of them works?  I believe that the local FTDI on the base board is a V1 based XDS100, but it all depends on the programming file.

Best,

Matthew

Hi All,

Finally I managed to get it working, I used the last schematic orientation that Cody shared and connected the 3.3 V pin of the FTDI module to the JTAG connector header on the docking station with a 100 Ohm resistor. Also, it works with XDS100v1 configuration file and not with XDS100v2. 

thanks a lot!

rgs

Fra 

Francesco,

Great to hear. Feel free to start another post if you have more questions!

Regards,
Cody