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MISO is always high.

anil kunchala
Prodigy 60 points

Other Parts Discussed in Thread: CC2500

while reading the MISO Pin it is always giving the high Value.

channel 0 - mosi

channel 1 - clk

channel 2 - miso

channel 3 - csn

i checked the GDOo signal on power on reset it is giving the 137 khz. i think cc2500 is ok.

  • 0
    TI__Guru 56590 points

    Hello Anil,

    When do you see this? Is this right after power on, reset or wake-up from sleep? Do you also see this issue of you keep the device powered without entering sleep sates or resetting the device?

  • 0 in reply to Eirik V
    Prodigy 60 points

    right after power on.

     Do you also see this issue of you keep the device powered without entering sleep sates or resetting the device?

    i don't understand?

  • 0 in reply to anil kunchala
    TI__Guru 56590 points

    Hello Anil,

    We always recommend to poll CHIP_RDYn before sending data on the SPI bus but if this is not possible you will need to insert a delay equal to the max startup- time of the crystal after waking the chip from SLEEP, reset or power on. After reset you will see that CHIP_RDYn often is asserted (pulled low) much faster than the start-up time of the crystal, but to be safe, the start-up time must be used to account for worst-case timing scenarios.

    You can also try the following: look at the Reset chapter in Design Note DN503. Try to follow the procedure given there to wait for a stable clock

    Strobe CSn low / high.
    • Hold CSn high for at least 40 µs relative to pulling CSn low
    • Pull CSn low and wait for SO to go low (CHIP_RDYn).
    • ......