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Is CC2540 DMA working when CPU is in PM1 power mode ?

Sasha Kalmanovich
Intellectual 840 points
Other Parts Discussed in Thread: CC2540

I work with USART0 in UART mode, and use the DMA to handle the received data (using the driver in _hal_uart_dma.c).

Are the UART and DMA working when the CPU is in PM1 ? (Will it be possible to retreive the data transmitted to the CC2540 while it was in PM1 after waking up ?)

Thanks.

  • 0
    TI__Intellectual 1005 points

    The USART and DMA will not work when the device is in PM1. The USART and DMA will only work in normal/active mode and in PM0 (cpu halted).

    Regards

    Moe

  • 0 in reply to MaMoe
    Prodigy 10 points

    I would like to know if it would be possible to use DMA to transfer incomming bytes from USART in an SPI slave configuration (clk provided by external chip) in PM1 on the CC2540.

    I am somehow mislead by the DMA controller chapter on the user guide (swru191c) chapter 8, page 95, where it says:

    Use of the DMA can also reduce system power consumption by keeping the CPU in a low-power mode without having to wake up to move data to or from a peripheral unit (see Section 4.1.1 for CPU low-power mode).

    I would like to know if that 'low power mode' it is refering is just the IDLE state or it means PM1.

    Thanks

    Carlos

  • 0 in reply to Carlos Agell
    TI__Intellectual 1005 points

    The USART and DMA will not work in PM1.

    The CPU can be in a low power mode (IDLE) but the rest of the system needs to be active for the USART and DMA to work

    -M