AnsweredAssumed Answered

No repsonse from AD5272

Question asked by KMC500 on Nov 6, 2013
Latest reply on Nov 12, 2013 by KMC500



I am having some difficulty updating the output resistance value from the AD5272.


I have initiated communnications over the I2C. I have proven it is addressed correctly, the system is receiving acknowledges and able to complet e the 3x packet transaction as described in the datasheet. This has been measured with a scope.


I have tried to run the system using configuration bits to define direct update of the RDAC register and also updating via the 50TP spaces but I always have the default output of 10K.


Circuit Shown above.



And Data Plot showing SCL & SDA lines at a frquency of 80kHz, data sent in summary is as follows:


P1: 0101100000 - Adress, Write & Ack

P2: 0000001110 - Config to Update RDAC, D9 & D8 = 1, Ack

P3: 1111111110 - D7-D0 = 1, Ack



This should write 1023 to the RDAC giving full scale. Regardless of what data I send the output is fixed at 10K.


It may be that I am doing something obviously incorrect here but I would appreciate anyones feedback who knows this part well.


Many thanks in advance,