Ad5757 from eval board doesn't answer



I have evaluation board with AD5757 for two days. I would like to check that communication is working properly, so I want to read data from register without success. The second option is to turn on alarm led on the board by watchdog because of no communication.

I have no clue why it does not answer me. I checked communication twice with logic analyzer and once with oscilloscope.


Eval board is connected to Raspberry pi. You can see script, which I use to test communication.

As a summary I can say that I use 0x9C, 0x2F, 0x00 to enable watchdog for 200ms and then wait 2 seconds without communication.

Then I send 0x98, 0x00, 0x00 to read status register and afterwards I send no operation 0x1C, 0xE0, 0x00.

Could someone confirm that this sequence is the correct one please?

I can provide dump from logic analyzer if required.

If more details is necessary feel free to ask.




import spidev

import RPi.GPIO as GPIO

from time import sleep

import sys





spi0.mode = 1




GPIO.setup(7, GPIO.OUT)

GPIO.setup(11, GPIO.OUT)

GPIO.output(7, GPIO.HIGH)

GPIO.output(11, GPIO.HIGH)



print spi0.xfer2([0x9C, 0x2F, 0x00])


print spi0.xfer2([0x98, 0x00, 0x00])

print spi0.xfer2([0x1C, 0xE0, 0x00])


GPIO.output(7, GPIO.LOW)


GPIO.output(7, GPIO.HIGH)