• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 30 subscribers
  • Views 607 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Failed to erase flash CC85xx

Pavel Ruzicka
Expert 1720 points
Other Parts Discussed in Thread: CC8521, CC8531

I can't program any of my four boards. It fail on erase flash. CC debugger with latest firmware has green LED and correctly detect device CC8521 and CC8531 in my case. I red some previous articles http://e2e.ti.com/support/low_power_rf/f/382/t/63012.aspx and there are informations about not functional crystal. I don't know if crystal works correctly. I have 48MHz crystal with parameters Load capacitance 18pF and ESR 80ohm max. On the board I have capacitors 16pF. In datasheet for CC85xx are parameters Load capacitance 16pF and ESR 60ohm max. I haven't much experience with crystals. Is it possible, that a slight different parameters are key of my problems? I have 3.27V on all VDD pins.

Schematics diagram added: 3414.cc85xx.pdf

  • 0
    TI__Expert 7160 points

    Hi Pavel,

    Are you in posession of one of the TI EVMs? If so you could try to solder off the crystal and capacitors from the EVM and replace with your crystal and caps.

    Best regards

    Kristoffer

  • 0 in reply to Kristoffer S
    Expert 1720 points

    Thanks, but I haven't EVM. I tried parallel solder two capacitors 16pF, that now there are about 32pF capacitors, but it didn't help. Today I bought another crystals, that I will try to change them. Now I haven't oscilloscope, but I will get them in a few days. Next I also check if oscillator running and on what frequency.

  • 0 in reply to Pavel Ruzicka
    Expert 1720 points

    Hi, I today changed Crystal, but without success. I also measured my boards with oscilloscope and all 48MHz crystals oscillates on 16MHz. Do you have idea, what next? Is it possible to change capacitor values to lower values? What are recommended capacitor values? In datasheet are not much info about it and in evaluation boards I see 27pF. I tried 16pF and 32 (2x 16pF in parallel) and it is still same. Thank you.

  • 0 in reply to Kristoffer S
    Expert 1720 points

    I found, why it doesn't work. My crystals are 48MHz crystals on 3th overtone frequency. Their are practically 16MHz crystals. I have two choices now. I can try to find crystal with 48MHz fundamental frequency, which is not easy, because their are not usual. Usually exists crystals up to 20MHz fundamental frequency. Another choice is to make parallel LC filter on the oscillator output to the ground for filtering fundamental frequency 16MHz. It is possible, that crystal will oscillate on 3th overtone frequency 48MHz.

  • 0 in reply to Pavel Ruzicka
    TI__Expert 7160 points

    Hi Pavel,

    Check out X1 in the part list of the TI ref design: http://www.ti.com/litv/zip/swrc185a

    -Kristoffer

  • 0 in reply to Kristoffer S
    Expert 1720 points

    Hi Kristoffer,

    thank you very much. I got other crystal model 406 from CTS company. It has 48MHz fundamental frequency and it works perfectly. Maybe it is a good idea to update datasheet with information, that it is not possible to use crystal with 48MHz on the 3rd overtone. Only crystal with 48MHz on fundamental frequency can be used.

    Until now I had not idea, that there exist something like crystal with 3rd overtone frequency ;-)

    Pavel