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CC2640R2F: Device doesn't power up after being programmed

PATRICK OHARA
Genius 3205 points

Part Number: CC2640R2F

Hello,

Oddly when I plug my implementation (shown below) in via the JTAG connector the CC2640r2 powers up and advertises. However, when I simply apply power to the VCC (3.3VDC) the device doesn't begin advertising. I can program the device and things work from CCS in debug mode fine. Also, if I leave VCC connected and disconnect the JTAG the device continues to operate - advertise, etc. However, if I remove VCC and then reapply power, the CC2640r2 doesn't come back up. Do I need to do anything with the JTAG connector pins (like terminate them) to make this work?

Thanks,

Patrick

  • 0
    TI__Guru**** 223757 points

    Hello Patrick,

    Can you please try re-attaching your image?  I also recommend that you compare your hardware against the LAUNCHXL-CC2640R2F design files, specifically where the JTAG connections are concerned, to further understand what the issue could be.  You may also want to monitor/scope your device connections to make sure they are pulled properly, especially concerning the reset line.  Finally, you can submit your design to SIMPLELINK-2-4GHZ-DESIGN-REVIEWS if you continue to experiences issues so that it may be reviewed by TI's hardware experts.

    Regards,
    Ryan

  • 0 in reply to Ryan Brown1
    Genius 3205 points

    Hi Ryan,

    Thanks for the suggestions. I've measured the JTAG connections and things look pretty normal. Paying particular attention to the n/RESET line, I measured the resistance from n/RESET to GND = 8.8 Mohm while the Launchpad measures 11.5 Mohm to GND. The resistance from n/RESET to VDD is 64.4 Kohm while the Launchpad from n/RESET to WMCU_VDD is 62.9 Kohm. The module from Laird that I'm using has an internal 100 Kohm pull-up on the n/RESET line. n/RESET measured during programming shows two 50 mSec pull down separated by 2.2 seconds (shown below).  So things look pretty similar (good).

    If I disconnect the JTAG connector with VDD applied from an external source (Keithley 2281S Power Supply) the CC2640r2 continues to advertise and operate as expected. As mentioned before, if VDD is disconnected and reconnected the CC2640r2 no longer advertises. Also, if the JTAG connector is disconnected and I touch the n/RESET line with my meter probe (Keithley DMM6500) to measure the voltage, the CC2640r2 stops advertising and as usual cannot recover after disconnecting and reconnecting power.

    As you suggest I'll submit the design for help.

    Thanks,

    Patrick

  • 0 in reply to PATRICK OHARA
    TI__Guru**** 223757 points

    Thank you for providing further detail in your response.  If I'm looking at your schematics correctly, then I believe the issue is that the RST line does not have an external 100 kOhm pull-up resistor and 100 nF pull-down capacitor.  I am looping in the SimpleLink Hardware Team for further feedback.

    Regards,
    Ryan

  • 0 in reply to Ryan Brown1
    Genius 3205 points

    Hi Ryan,

    There is a 100 Kohm resistor on the RESET line, it's inside the module from Laird. I'm not sure about the 100 nF cap.

    As with most things, this turns out to be user error. The device requires a very specific sequence of programming the CC2640r2. This is particularly true when using the OAD feature. The device needs to be reprogrammed each time - Stack, then App, then BIM. Having not used this program for a while, I'd forgotten this, and I simply reloaded the app (which works in non-OAD mode). With the CC2640r2 programmed in the proper sequence, the device works as expected - advertises and allows interaction.

    Thanks again for your help,

    Patrick