Dear sir/madam,
im trying to interface tms320f28379d with ads7841 via spi but getting random junk with or w/o connecting voltage to selected channel through control byte .
check screenshots and correct me if
im wrong.
Hello,
the best way to debug code is through a visual check of the communication. Connect probes to the digital bus to verify that the code is doing what is expected.
To debug, I suggest using a known DC input at the analog input, this will allow to compare the output measurement to the expected output.
you can then use the scope shot and compare to the timing diagrams in the datasheet to confirm al timing requirements are met.
Taking a closer look at the scope shot, it looks like the DIN is not synced with the clock.
The DIN bit should change at the falling SCLK edge and be stable at the rising edge of SCLK to be read by the device.
The start bit in DIN should be high before the first rising SCLK as well.
Regards
Cynthia
Im using 15 clock cycles and command byte was 0x97 using channel 0(0v was given as input),mode bit was low (12bits conversion),single ended and always power on ,CS pin was low always.But how im getting high on Dout when 0v connected.Is anything wrong,im using toggling operation on pins for CLK,CS,DIN(writing),DOUT(reading) not spi.
i've connected 3.2 v to channel0 and vref and vcc for ads7841 is connected to 3V the expected output is 4096 from SOMI pin but data was as screenshot above .please verify SOMI whether it was alright.
