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Using PIN CONTROL to switch from Sleep to Rx mode

efi rushinek
Intellectual 310 points

I want to exit the sleep mode by using pin-control instead of SPI commands (because time is critical). I couldn't do it with pin-control for RX, I have to go first to Idle. Is it like that also when using the pin-control ?

Should I also validate that the device is in idle mode before using the pin-control for RX? Is there a way to validate idle mode not by MARC status i.e. I want to avoid using SPI because of timing. Instead of reading MARC, can I use a fixed delay between pin-control of idle and pin control of Rx? What is the time delay?

  • 0
    TI__Guru* 86111 points

    Hi

    Looking at the state diagram you will see that it is not possible to go directly from SLEEP to IDLE. The chip must go via the IDLE state, but this does not mean that you need to strobe IDLE first and then strobe RX. You wake the chip from SLEEP by pulling CSn low. As soon as the crystal is stable, the CHIPRDYn signal will be asserted and you can send your RX strobe. The radio will then go to RX (via IDLE). The same thing should be the case with the pin control. You set CSLK and SI to 1 and pull CSn low. The radio will then enter RX from SLEEP via IDLE.

    BR

    Siri

  • 0 in reply to Siri
    Intellectual 310 points

    Just to double check; The sequence using the pin-control is as following. 1) polling CSn low. 2) waiting for CHIPRDYn signal. 3) Pulling CSn up . 4) setting SI and SCLK to 1 and then pull CSn low second time. This sequence is needed to move from sleep to rx mode! Please confirm

    About CHIPRDYn signal; SO goes low immediately when CSn goes low after being in sleep-mode, so SO=0 doesn't mean that the crystal is stable. For this case the CHIPRDYn signal should be asserted by the GPIO - please confirm.

  • 0 in reply to efi rushinek
    TI__Guru* 86111 points

    As long as SI and SCLK is set correctly for RX mode and the chip is configured for Pin control you should only have to pull CSn low once. The radio will then wake up from SLEEP and go to RX via IDLE.

    If MISO goes low immediately after pulling CSn low, this means that the crystal is stable. If the radio has been in SLEEP, the crystal is NOT stable when waking up so my guess is that the radio has not been in SLEEP mode at all. Have you configure that the radio is in SLEEP by measuring the current consumption? Note that the radio can only be taken into SLEEP mode from IDLE state.

    Siri