7 Replies Latest reply on Jun 22, 2016 10:30 AM by Intel Corporation

    Hardware execution of Intel edison baord

    rahul147258

      Hi ,

       

      I  am interfacing an analog sensor with Intel Edison  breakout board for Arduino.

      now I am in confusion by seeing the architecture that the analog data which comes from sensor giving to pin no "A0" of break out board.

      Can u tell me the data from MUX goes to ADC then from that ADC the communication is happing in SPI0 port.

      or can u tell me "what  Communication it is happening from MUX to Intel Edison"??????

      is it GPIO or I2C or SPI0 via ADC or hOw????????

      I am sharing u architecture

       

      Thanks

       

      I have assumed SPI0 communication am I right?? if yes means can u give justification...

       

      Thanks make it soon..

        • 1. Re: Hardware execution of Intel edison baord
          Flo1991

          If you look in the schematic (http://www.intel.com/content/dam/support/us/en/documents/edison/sb/edison_arduino_hvm_8_26.pdf )

          you can see what is done:

          The analog in is multiplexed with the chip 74LVC2G53 so you can either use the pin as analog in or as normal gpio (called MUX in the figure above). Furthermore the used ADC (ADS7951) has an internal multiplexer to

          get more than one ADC channel. The communication between the edison and the ADC is done by SPI.

           

          So for using the ADC internally the SPI0 bus is used to communicate with the ADC, an I2C bus is used to set the MUX 74LVC2G53 to ADC input (see Port Expander - SEL & Pull up in the figure above).

           

          In short: you are right, SPI0 communicates with the ADC

           

          Flo1991

          • 2. Re: Hardware execution of Intel edison baord
            rahul147258

            Ok thanks flo1991

            thanks for ur information.

             

            however  I know he data from ADC to Intel Edison communicate using SPI0 port interface.so u mean ADC acts as slave and Intel Edison acts as master o communicate right?? is that so..

            correct me if I am wrong. My    understanding is Intel Edison will communicate with ADC 7951 but which device acts as salve and which one master. Can u give me bit detail about that...??how the data transfer takes place from ADC7951 output to Intel Edison.

             

             

             

             

            thanks

            • 3. Re: Hardware execution of Intel edison baord
              Flo1991

              You are right, the edison is the SPI master and the ADC is the slave.

              If you are interested in the whole communication over SPI you must read the ADC datasheet, see page 24 and the followings (http://www.analog.com/media/en/technical-documentation/data-sheets/AD7951.pdf )

              The master starts the communication with a falling edge on the CS line. The master always provides the SCLK, the data from the master is sent over the MOSI line (master out slave in), the

              slave answers on the MISO line (master in slave out). MOSI or MISO may be unused/missing if no data is sent in this direction. The names of the lines (CS, SCLK, MOSI, MISO) may be different.

               

              Flo1991

              • 4. Re: Hardware execution of Intel edison baord
                rahul147258

                thanks ok

                how many analog sensor can be Connected to since according to adc7951 8 channels are there what does it infer..

                shall I connect 6 analog sensor so to utilize all channel of ADC7951.correct me if I wrong?

                if rt..can u provide some procedure to configure the different analog sensor??

                 

                thanks 

                • 5. Re: Hardware execution of Intel edison baord
                  Intel Corporation
                  This message was posted on behalf of Intel Corporation

                  Hi rahul147258,

                  You can connect up to 6 analog sensors using the pins A0 to A5 that are available on the Arduino expansion board. In order to read the analog values from these inputs, you can use the Arduino IDE which provides useful examples for this purpose. I recommend you to check the example AnalogInput or the example AnalogInOutSerial to use the ADC. They are available under File>Examples>Analog

                  Regards,
                  Diego

                  • 6. Re: Hardware execution of Intel edison baord
                    rahul147258

                    Hi Diego,

                     

                    what is meaning of 8 channels present in  ads7951 which are mounted on Intel Edison arduino expansion (CH0 to CH7).

                    when I fetch an analog sensor from pin A0 which channel it configures and how??

                    As per my knowledge they say 16 clocks will be 1 frame. Among which first 4 bits will be channel address and remaining 12 bits for data conversion and farther process..am I right??

                    however I wanted to know how that address of channels will get selected ?? and  all channels ..

                    In short can u tell  me reason of multiple channels in ADC7951 IC.

                     

                    THANKS...

                    • 7. Re: Hardware execution of Intel edison baord
                      Intel Corporation
                      This message was posted on behalf of Intel Corporation

                      Hello rahul147258,

                       

                      The ADS7951 has 8 channels, however, only 6 channels are used. The channel 0 corresponds to the A0 input, the channel 1 corresponds to the A1 input and so on. Take a look at the following schematic that corresponds to the ADC circuit used in the Arduino expansion board. You can see that only the first 6 channels are connected.

                       

                      ADC.JPG

                       

                      The details about how the ADS7951 works can be found in its datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/AD7951.pdf

                       

                      In general, the ADCs have more than one channel in order to attach more than one analog input, however, there is only one "ADC unit". This means that only one analog-digital conversion can be done at a time. Once the first conversion ends, the next one starts. There are conversion time requirements that have to be met, otherwise the conversion won't be successful. Anyhow, I recommend you to check the ADS7951 datasheet for specific details about this IC. If you want to know how ADCs work in general, I recommend you to check the following article: Analog-to-digital_converter

                       

                      Hope this help you.

                       

                      Regards,
                      -Diego