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CC1000: CC1000

Yossi Saiet
Prodigy 10 points
Part Number: CC1000


We are using CC1000 as a RF transmitter for many years now without problems. Lately we find that 50% of our boards with CC1000 pass calibration but fail to transmit any RF signals.

1. Checking the pins of the CC1000 I found only one difference between a working board and a failing board:

- On a working board, pin 12 CHP_OUT (LOCK) is mostly "H", except for short periods of 2.5ms over a cycle of about 350 ms. I try to transmit about every 300ms.

- On a failing board, pin 12 CHP_OUT has an inverted signal. Mostly "L", except for short periods of about 0.5ms over a cycle of about 350 ms.  I try to transmit about every 300ms. 

2. Lock Register 0xD is programmed with the value 0x10.

3. Following are the values of all the registers from register 0- 0x1C :

 0x00, 0x47, 0x06, 0xD4, 0x47, 0x06, 0xD4, 0x03,
0xB4, 0x91, 0x02, 0xFF, 0x50, 0x10, 0x26, 0x8D,
0x6F, 0x46, 0x70, 0x01, 0x00, 0x16, 0x10, 0x0A,
0x06, 0x03, 0x01, 0x0D, 0x00

  • 0
    Prodigy 10 points

    4. Do you have an idea why the transmit is failing?

    5. What steps should be taken to isolate the problem?

    Thanks,

    Yossi

  • 0 in reply to Yossi Saiet
    Prodigy 10 points

    I have just noticed that bit PLL[1] (ALARM_H) of register PLL Register (0Ch) is "H". Why is this and what should be done?

  • 0 in reply to Yossi Saiet
    Mastermind 6590 points

    I assume that you haven't done any changes in production (the PCB, BOM and FW is unchanged)?

    If that is the case, could it be a problem at the assembly house (one or more components have wrong value etc)? 

  • 0 in reply to Yossi Saiet
    TI__Mastermind 18695 points

    Hi Yossi,

    As TheGhostOf mentions in his reply above, if the boards/devices have previously all worked without issue, have there been any production changes?

    Have you tried an ABA swap between working/failing boards?

    Regards,

    Zack

  • 0 in reply to ZC
    Prodigy 10 points

    1. We had changed the CPU because of EOL of some parts. After the change some boards worked with the new CPU work and others failed

    2. To identify the problem, I tried ABA between a working board and a failing board. Seems now have a slightly different problem.

    3. After doing ABA of VCO inductor L101 (between pins L1, L2) of the two boards, Pin 12 CHP_OUT (LOCK) is mostly "H" now on both boards. So, we have LOCK_CONTINUOUS.

    4. I noticed that ALARM_H of the PLL register (0xC) is still always high. For both boards.

    5. Now for both bords no RF signal is transmitted. if I change one byte in the data I send, from 0x02 to 0x22 the boards send the data message.

  • 0 in reply to Yossi Saiet
    Prodigy 10 points

    1. To sum up my findings. I just checked with a spectrum analyzer, and I saw that for boards that are okay, we see two peaks. One for the high frequency and one for low frequency. For boards that fail, we only see a peak for the low frequency. For the high frequency, there are a lot of different frequencies and no peak at the expected high frequency.

    2. As I understand this fits the ALARM_H indication we see in the PLL register (0xC).

    3. This means I need to go back and use the configuration software SmartRF Studio for CC1000 find the correct register values.

    4. Looking on the internet it suggests using SmartRF version 6 that supports CC1000. On the internet I could only find version 7 and 8 that don't support CC1000.

    5. Do you agree with my findings?

    6. Can you send me SmartRF version 6 so I can find the correct register values to support my high frequency.

    Thanks, in advance.

    Yossi

  • 0 in reply to Yossi Saiet
    TI__Mastermind 18695 points

    Hi Yossi,

    I will reply regarding the rest of your findings shortly, but you can find the SmartRF Studio v6 download link here: https://www.ti.com/tool/download/SWRC046

    Regards,

    Zack

  • 0 in reply to Yossi Saiet
    Mastermind 6590 points
    Yossi Saiet said:
    We had changed the CPU because of EOL of some parts. After the change some boards worked with the new CPU work and others failed

    It doesn't sound like that the MCU is the issue but have you tried to rule out the MCU? Could changed timing be part of the issue? I assume you have tried to read out the registers to confirm the value.

    Yossi Saiet said:
    After doing ABA of VCO inductor L101 (between pins L1, L2) of the two boards, Pin 12 CHP_OUT (LOCK) is mostly "H" now on both boards. So, we have LOCK_CONTINUOUS.

    What you describe indicate a issue with the VCO and more so with the external components. Has it been other BOM updates that could explain why L101 should be off?