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.

CS Response Time Of CC112x

Hello,

In the page 4 of the swra428a. It  specify that we  need 4 bit to setting AGC base on CS.

But the figure in the page 13 of the swra413, There is not need 4 bit for CS time.

(ex: line2, 868Mhz,Bit rate: 1.2 kbps, 2-FSK, RX BW: 50 kHz)  it's use shorter than 1 bit 

i want to know about the relationship between these.

Best Regards,

Mark

  • Hi Mark

    You need 4 bits preamble to make sure that you will be able to receive the following sync word. The radio can however determine if there is a signal or not on the air (CS) in less than this time. Even if it detects a carrier during a 2 bit period, it does not mean that it would be able to detect the sync word correctly.

    When implementing sniff mode you always must make sure that you wake up early enough to receive at least 4 bits preamble before the sync word. The CS response time gives you info about how long the radio will stay in RX before it goes back to SLEEP given that there is no signal on the air.

    Siri

  • Hi Siri

    thank you for your answer.

    I still a question about the AGC and AFC. Following your answer the AGC and AFC adjustment not in the 4 bit preamble.
    but when is the time to adjust the AGC and AFC. Is it work in the carrier?

    Best Regards,

    Mark
  • Hi

    For the AGC to settle you do not need a preamble, just a signal of duration longer than 4 bits. The reason we are referring to preamble is that most radios needs a preamble to do bit sync. This is not the case with the CC112x due to the WaveMatch feature used to detect sync.

     Siri