Bob: Thank you very much for your quick response -Please find attached the ADC schematic -The ADC interfaces with a microchip PIC32 microcontroller (PIC32MX795F512L-80V/PF) via a FPGA device -The interface is a 8bit bus to SPI -Polarity is set to falling edge -What I am not clear is how do you read all channels in sequence ?? (if you have any code example of how to read channels in sequence please email me a copy) - I can read all registers correctly evey time -This is what I am doing: only once after power up: Set Reg 0 = 0x0C : fosc/128 + Int VRef enable + Int Vref = 2.5V + buffer disable + most significant bit first (RA36 in the schematic is not installed, not ext VREF) only once after power up: Set Reg 9 = 0x47 : Unipolar + auto settling top: Wait for "start conversion flag" from microcontroller Set "adc busy flag" for micro read channel" set Reg 1 = channel number + 8 = AIN comm ( 0x51 + 0x00 + ch# + 1000b) 200ms delay check if DRDY pin is low (data ready) Read data 24b and store (0x01 than read 24 bits clear "busy flag" micro reads data go back to "top" Thank you again for your help Fausto Bartra(Please visit the site to view this file)
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