cc1101 signal receiving problem

Hi Shuozhi

It is hard to determine the cause of this without more information.

Is it possible to post your register settings and  code snippet for the TX and RX operation?

Br

Martin

Thanks for your reply! I actually already solved the problem. It might be caused by the SPI register writing/reading timing.  I don't know if this a common issue. I used MSP430F1232 and MSP430F2274 in my two ends, and the same SPI register access timing problem occurred for both MCUs, which operate in different frequencies (4.9MHz and 16MHz). SPI baud rate is a half of the MCLK speed. I don't see any documentation on the timing after writing/reading the radio register, or maybe I missed them.

Originally, I used the same code as provided in the MSP430-to-CC1101 interfacing example program, and I had this issue for both MCUs. I added some delay to each of the the SPI register access functions from MSP430-to-CC1101 interfacing example program, and all the data look alright now. For example:

void TI_CC_SPIWriteReg(char addr, char value)

{

  TI_CC_CSn_PxOUT &= ~TI_CC_CSn_PIN;        // /CS enable

  while (!(IFG2&UTXIFG0));                  // Wait for TX to finish

  U0TXBUF = addr;                           // Send address

  while (!(IFG2&UTXIFG0));                  // Wait for TX to finish

  U0TXBUF = value;                          // Send value

  while(!(UTCTL0&TXEPT));                   // Wait for TX complete

  TI_CC_CSn_PxOUT |= TI_CC_CSn_PIN;         // /CS disable

  TI_CC_Wait(45);

}

If there is any explanation on this, I would really appreciate!

Thanks!

Can you read from the registers? This will ensure that the SPI connection is working correct. Try to read out the part number (should be 0x00) and version number (should be 0x04).

If the SPI connection is working, that you should check the settings of the packet length and packet mode. You have to choose if you want to sent a packet in variable, fixed of infinite mode. The most easiest way to check of the wireless connection is working, is to send an packet of 10 bytes, where the packet length  is 0x0A and the packet mode is fixed. You should also turn the CRC16 and status append off.

greetings,

Rick

Yes, reading and writing to the registers are all fine. I read all the registers one by one after writing the initial settings to them. 

I actually found the problem, the example code does not check the status of the radio core. When it enables CS pin, it only uses the following code to check the status of the SPI interface:

{

TI_CC_CSn_PxOUT &= ~TI_CC_CSn_PIN;        // /CS enable 

while (!(IFG2&UCB0TXIFG));

}

However, according to CC1101 transceiver manual page 28, MCU must wait till SO pin goes low indicating the radio core crystal is running. So I added one piece of code in between.

{

TI_CC_CSn_PxOUT &= ~TI_CC_CSn_PIN;        // /CS enable 

while(TI_CC_SPI_USCIB0_PxIN & TI_CC_SPI_USCIB0_SOMI);

while (!(IFG2&UCB0TXIFG));

}

Now everything is working well. Thank you very much for all you guy's help!

Yang