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I2C/SPI communication between two devices without MCU

Albert Lu
Prodigy 20 points
Other Parts Discussed in Thread: ADS7040

Hey All,

Is there away to transfer the data between two i2C or SPI devices without using a micro controller? For example, I have a nRF2401 SPI based 2.4 GHz transmitter and a SPI temperature sensor.  How can I just make the temperature sensor constantly dump data to the SPI 2.4 transmitter with out a MCU? Is there a programmable device that can generate the clock, with the correct timing?

  • 0
    TI__Genius 16430 points
    Hello Albert,

    Unfortunately, this is not the way I2C works. In I2C, the spec states that a slave device must be explicitly called/addressed by a master/some device requesting the information.

    You will have to address the device by writing the device's address to the I2C bus (SDA and SCLK lines) and then requesting a read operation from it in order to get data.

    As for SPI, SPI does not explicitly define a method that data must be transferred. Therefor This question is difficult to answer without device datasheets that outline what procedure you must follow to retrieve data from them.
  • 0 in reply to Jonathan Valdez
    Prodigy 20 points
    How about lets take ADS7040 as an example, All it needs is a SLK and SCLK. How can I generate these two signals without using a MCU?
  • 0 in reply to Albert Lu
    TI__Genius 16430 points
    Albert,

    Take a look at the datasheet of the ADS7040 on page 17. It shows that to get data out of the device, you need to pull !CS low, pulse a clock signal 10 times, and the data will output from the device. Perhaps your nRF2401 device will allow you to do this? I am not sure. Our ADCs were made to be connected to a microcontroller like the MSP430.