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Initialisation AD7280

Question asked by martin89 on Jul 7, 2015
Latest reply on Jul 28, 2015 by jcolao

Hello there, 

I have a question to the AD7280.  

For my Master Thesis I want to build a battery management system for 16 cells. In this case I have three AD7280 in a daisy-chain.  

The main chip is a AT90Can128.  

Now there is a problem with the initialisation. 

After a waiting time of 20 ms, CS=0 and I send the message 0x01_C2_B6_E2. After
this the CS is reset to 1. 

After a waiting time of 5 us, CS is set to 0 and I send the message
0x03_87_16_CA. After this the CS is reset to 1.

For the last step I wait 5 us, set CS to 0, send the message 0xF8_00_03_0A and
read the result. After this I reset the CS to 1 and wait 5 us. Then I repeat
the last step 2 times. 

This is all from example 1 on page 39 of the data sheet. 

I have two boards with this configuration. As read back I got on one board from
chip 1 the right result and from chip 2 and 3 only zeros. 

On a second board, I got the right results from chip 1 and 2 and chip 3 gives
only zeros back.

Now I don't know if there is a software problem or a hardware problem. The
boards and the code are exactly the same.

I hope you can help me. 
Yours faithfully 

Martin Heger