Hi, We are using an AFE5809EVM board, with the SPI bus connected via wires to our product board which is under development. We can successfully and reliably read and write registers in the 5809's ADC/VCA block. However, reading registers in the Demod block is unreliable. If we write a Demod register, then read it back, sometimes we get the value we wrote in and sometimes we get zero. On an oscilloscope we can see the SPI sequence writing a Demod register and reading it back, but the 16 actual data bits returned are sometimes present and sometimes zeroes. We have experimented with slower clock speeds, the relative timing of SEN and SPI_DIG_EN, chip cooling etc. The timing of the signal lines matches the data sheet timing diagrams. The intermittent nature of this issue feels like a marginal timing problem somewhere. Can you suggest what may be causing this? Thanks, Duncan Hurst Fen Technology Ltd. Cambridge, UK.
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