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AWR1243: Question about SPI timing/protocol

Part Number: AWR1243

Hi,

Would you pls help my below questions?

1. In 5.9.3.2 Typical Interface Protocol Diagram (Slave Mode) of AWR1243 datasheet, I found below info. Must it be two spi clocks delay or the min is 2 spi clocks?

Host should ensure that there is a delay of two SPI clocks between CS going low and start of SPI clock.

2. In Figure 5-5. SPI Communication, it seems that spi of AWR1243 will sample the data on the falling edge of the clock. Must it be falling edge?

  • Hello Chris,
    The CS should be high for atleast 2 clock cycles (can be larger) and there should be min 2 clock cycles before starting the SPI clk (after CS is pulled low).

    In case of 1243 the SPI interface clock edge is fixed , it cannot be changed.

    Regards,
    Vivek
  • Vivek,

    I tried to detect the SPI signals on xWR1443 EVM+devpack when I click the spi connect button in radar studio. And I found the xWR1443 spi will detect the data on the rising edge of SPI clock as the signals shows below, instead of falling edge in the Figure 5-5. SPI Communication of AWR1243 datasheet.  Would you pls help to check if it is a mistake in Figure 5-5. SPI Communication in AWR1243 datasheet?

    ch1: spi_cs

    ch2: spi_clk

    ch3: spi_MOSI

  • Hello Chris,
    You are right , the host sends the data (MOSI) on the falling edge of the CLK. We will correct this in the datasheet.

    Regards,
    Vivek