AD7386 in One Wire mode

Question

I am unable to get an AD7386 working in One Wire Mode. I have tried two devices with the same result. 
 I have set and read back configuration registers 1 and 2 correctly with Register 2 bit 8 set but data only streams out on SDOA and SDOB. 
 I am using a dsPic33FJ device to read the data on it's SPI input and Channel A always appears but Channel B on the next 16 bit transfer is always 0x0000. 
 I have verified this on an Oscilloscope and the second SPI transfer on a single CE cycle always returns 0 volts. 
 Above is a scope photo of the SPI transfer. The top trace is the CS, the blue trace is the SCLK and the bottom trace is the SDOA output. 
 I have tried various timimg to no avail. Has anyone used this device in One Wire mode? 
 Can anybody help please? 
 Thanks 
 Steve

jcolao · Accepted Answer

Hi Steve, 
 The last SCLK cycle can be ignored. In that picture that short pattern runs repeatedly. It was a quick pattern verification to quickly confirm the write to the register for the 1 wire mode. I think the gap between two sets of 16SCLK cycles is OK. I also tried running this pattern with a wide gap between two sets of 16 SCLK cycles. I don't think the pad will affect. 
 Just curious, have you check when no data output on the SDOA for channel, does it have data out[ut in the SDOB pin? 
 
 Regards, 
 Jonathan)

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AD7386 in One Wire mode

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