This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

SN65HVS882: When all 8 digital inputs are active (high level=24V) the SPI reads 00

Part Number: SN65HVS882

Hi there,

we have designed a new board that has to read 48 digital inputs. The board is 24V power supply, also inputs can be 0V or 24V.

We connected 6 devices SN65HVS882PWPRG4 together using SPI interface in chain mode.

All works well when inputs are different from "11111111", but when all 8 digital inputs are at logic high the device reads 0.

When 7 digital inputs are at logic 1 and one of them is at logic 0 the SPI reads good values and the same for all the combinations, except 11111111.

This happens for each of the 6 devices.


Current consumption at each input is limited setting current limiting resistance, we tried with 3mA and also 1.5mA but behaviour is the same. What I noticed is that connecting one input at time at 24V and measuring input current, the current increases a little bit more connecting the last 4 inputs and it reaches a maximum value when 7 inputs are high, the last input makes the current to decrease a little bit and SPI reads 0.