CC1101 Incorrect Bytes in RX FIFO

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Posted by Ben Walpole

on Sep 09 2011 03:36 AM

Hi,

I'm using a CC1101 in conjunction with an MSP430, the CC1101 is set-up to us fixed length packets, no address check, no CRC and to append status bytes to the ends of packets.

I have a strange problem where the last three bytes of a received message are always wrong, the status bytes that follow look to be correct since the RSSI value is moving in line with the power used in the transmitter. This behaviour is consistent and doesn't change no matter how long the message it always the last three bytes that are wrong. Any ideas as to what could cause this?

I have an interrupt in the MSP430 that fires when a packet is received, I then query the RXBYTES register to confirm there are enough bytes in the RX FIFO and then do a burst read. I dont think this can be an SPI problem since the status bytes seem ok, its just the last three bytes of the actual message.

Thanks,

Ben

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Posted by Ben Walpole

on Sep 12 2011 05:47 AM

Intellectual770 points

Hi,

This turned out to be a problem with my code, I was putting the CC1101 into RX mode to soon and not allowing all the bytes of the message to be transmitted. I've added extra checks to ensure the code waits for the transmission to finish and now all seems fine.

Thanks,

Ben

Posted by Jim Noxon

on Sep 12 2011 10:13 AM

Genius14940 points

An excellent job of debugging!

I apologize for missing your first post but I'm glad you responded with your solution. These problem/solution types of posts are perfect for helping others with similar issues.

Thanks for contributing,

Jim Noxon

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Posted by Fatima M.s

on Aug 01 2012 06:08 AM

Prodigy10 points

I'm having almost the same problem, I send 30 bytes.

I receive 1st to 16th bytes correctly then 3 bytes wrong values then the other 11 bytes correct again.
first I thought it's noise but this 3 bytes wrong values are always the same for a specific data. and it's always bytes number 17-19.
does anybody know why this is happening?

thanks