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
I have assumed SPI0 communication am I right?? if yes means can u give justification...
Thanks make it soon..
If you look in the schematic (http://www.intel.com/content/dam/support/us/en/documents/edison/sb/edison_arduino_hvm_8_26.pdf 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
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.
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 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.
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??
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
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.
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.
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 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: https://en.wikipedia.org/wiki/Analog-to-digital_converter Analog-to-digital_converter
Hope this help you.