Hi there - having trouble picking up slave(nano\mega\other board) on uno. Have ran the i2c scanner will pick up an address. Same wire connected to an i2c lcd works fine. Have use pullup resistors no change. Yes A4 (sda) to a4, A5 (sla) to a5 Have tried a mega to uno, nano to uno, no change Doing…

Always show us a good schematic of your proposed circuit. Show us good images of your ‘actual’ wiring. Give links to components.

Sorry guys - pretty “simple” wiring - 4 wires gnd,5v a4 (sda) to a5 (sla) to another device, will take some pituces in the am.

What do you mean by “not picking up”? If the I2C scanner found the slave, then maybe has something to do with the code on the slave.

Since you haven't posted your code so we can't tell, but are you starting the I2C bus on the slave Arduino with a slave address? If you don't specify the slave address, it will just start as a master. https://docs.arduino.cc/language-reference/en/functions/communication/wire/begin/ Please post bot…

Here is my i2c slave test code. Should show as address 13. I have the i2c master to go with this if you want it. #include <Wire.h> byte array[8] = {2,4,6,8,10,12,14,16}; volatile byte regReq = 0; volatile byte* rtnPtr; void setup() { Serial.begin(115200); Wire.begin(13); Wire.onReceive(rece…

Does the scanner print any address at all? I ran the slave code from @SurferTim on a Nano against the standard I2C scanner example running on a UNO and it returned an address of 0x0D, which is what I would expect: 22:08:24.991 -> I2C Scanner 22:08:24.991 -> Scanning... 22:08:24.991 -> I2C device f…

Just running the i2c scanner program and finding no address, connect to an i2c lcd finds an address

Install and run my slave code above. You should get a device on 0x0D if the device is connected to the i2c bus..

Arduino unable to pick up slave on i2c

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Arduino unable to pick up slave on i2c

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