Recently we purchased one NI-8451 I2C/SPI board from National Instruments. Using the board I want to read digital data from Analog Device’s AD7767 24-bit ADC, which is daisy chainable with SPI interface (please refer Fig 36 and 37 in AD7767 data sheet ).
In my project I have cascaded 12 ADCs. The sampling frequency I am using is 16kHz. Hence in every 1/(16e3) sec I have to read 12x24=288 bits (=36 bytes). For this I am planning to use 12MHz serial clock from SPI board (NI-8451). Before reading the data I have to check the status of ~DRDY (data ready ) line from the ADC and start to read the data after the negative going edge of the ~DRDY signal from the ADC.
If we use a microcontroller, we can give the ~DRDY signal to an interrupt pin and write the read operation in the interrupt service subroutine. So how the same operation can be done using the NI-8451 board?
Thank you very much for your time.
Reju
