cc1101 continues to report of CRC errors and garbage data

TYB

Other Parts Discussed in Thread: CC1101

Hello,

I'm using a cc1101 chip connected to a overo-gumstix board. I use this set up as a transceiver in my project to communicate with another cc1101 chip connected to a MSP 430 micro controller.

I use 915MHz, frequency and 2-GFSK modulations scheme. The baud rate I'm using is 38kbps. All the registry settings for the cc1101 chip was obtained using the SmartRF software.

With the above settings I'm perfectly communicating with the MSP 430 device. But I have noticed that in certain times, when my cc1101 is in the receiving mode, I'm getting CRC errors and length violation data constantly, instead of actual data which is sent by MSP430. I have employed a frequency sniffer and I'm confident that the MSP 430 is transmitting perfectly. I doubt whether the cc1101 chip is stuck in certain RF receive states.

In general I send the SIDLE and SFRX strobes to the chip before starting any receiving modes. But still there are random times that I start observing only CRC errors and other garbage data.

Any help or views regarding this is highly appreciated.

Thnx.

Thilina

over 14 years ago

0 Mizanur Chowdhury over 14 years ago

TI__Genius 17270 points

Hi,

Did you try to implement packet length filtering and address filtering to see if that helps?

BR,

0 Jim Noxon over 14 years ago

TI__Genius 14940 points

Any chance the transmitting side is truncating the packet early? If the transmit side issues an IDLE command (aborts the transmission early) when the last data byte is sent, and if auto append of CRC is enabled, many times these bytes get truncated and then the receiver indicates failed CRC indications.

Another possibility is if you are reading the RX FIFO too fast and are under flowing the FIFO. In this case, the end of the packet will appear as garbage only because you are reading the data too fast. Make sure you are testing the amount of data in the FIFO before you read anything out of it. Generally the SPI interface is much faster than the data rate the radio operates at so this type of failure is common in new code designs.

Jim Noxon

0 Zhaohan Jia over 13 years ago

Prodigy 150 points

Hi,

Have you solved this problem?

I wonder to try similar thing to apply 868MHz interface, may be also cc1101, to the Gumstix board. Could tell me how to install CC1101 on overo-gumstix board?

Thank you!

0 Thilina Yapa Bandara over 13 years ago in reply to Zhaohan Jia

Prodigy 80 points

Hi,

I connected the CC1101 to the gumstix board and developed my own RF linux driver to communicate with the chip via SPI.

0 Zhaohan Jia over 13 years ago in reply to Thilina Yapa Bandara

Prodigy 150 points

Hi,

Do you use the TI's CC1101 directly, or use other TI's co-designer's CC1101 device?

Is that possible to share your driver or give some instructions? I am freshman on it.

Thank you!

0 Thilina Yapa Bandara over 13 years ago in reply to Zhaohan Jia

Prodigy 80 points

I used cc1101 EVM (http://www.ti.com/graphics/tool/CC1101EMK868-915.jpg)

Well the driver is a very simple SPI driver and I'm sorry I can't share the driver as it is a part of a current cooperate product. First thing is to create a simple SPI driver and test the proper communication between the gumstix and the cc1101. Then you can start the rest of the work.

You can start with this (http://www.jumpnowtek.com/index.php?option=com_content&view=article&id=57&Itemid=62)

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cc1101 continues to report of CRC errors and garbage data