Issue with RFM69 and ADS1220 on SPI Bus: RFM69 Stops Responding When ADS1220 is Powered

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1

I’m working with an Arduino Uno, an Adafruit RFM69 module, and an ADS1220 ADC, all connected via the SPI bus. The RFM69 module is powered with 5V and works perfectly when it’s the only device on the bus.

The issue arises when I add the ADS1220. Initially, I connect the ADS1220 to the SPI bus without powering it or connecting the Chip Select (CS) pin, and the RFM69 still functions as expected. However, as soon as I power the ADS1220 (even with CS still unconnected), the RFM69 module stops being recognized entirely.

I’ve verified the wiring and power supply, and I don’t suspect a power-related issue because the RFM69 works fine until the ADS1220 is powered. It seems like the mere presence of a powered ADS1220 on the SPI bus, without even selecting it, is somehow interfering with the RFM69.

Any insights on why the ADS1220 might cause the RFM69 to stop responding as soon as it’s powered, despite not being selected on the SPI bus?

2

Perhaps it doesn't tri-state MISO when it's not selected.

3

does the ADS1220 work OK when you run example test programs (without RFM69 powered)

4

Post a schematic showing how this is wired. Be sure to show all power connections and power sources.

5

Yes, perfectly

6

It works now, i didn't change anything to the wiring but now it works, thank u for your help

7

sounds like you may have a poor connection
using jumper wires to interconnect devices is an endless source of problems
try pressing on the wires - does it work intermittently ?

8

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