https://devzone.nordicsemi.com/f/nordic-q-a/778/nack-from-i2c-slaveHi i am using twi_hw_master.c for i2c communication of accelerometer. my accelerometer address is 0x18. once i call twi_master_transfer(0x18,dataW,1,1); in function ERRSRC is setting to 0x02, means there is no ack from slave. buten-USTelligent Community 13Mon, 11 Nov 2013 08:04:27 GMThttps://devzone.nordicsemi.com/thread/3921?ContentTypeID=1Mon, 11 Nov 2013 08:04:27 GMT137ad170-7792-4731-bb38-c0d22fbe4515:0bf7384a-17ee-4fb6-a470-af21d130b2e6Prasad<p>Hi Balaji</p> <p>for trouble shooting you&#39;ve two options</p> <p>(1) I request you to confirm that slave address that you have given is correct, in the examples in SDK the slave address used is as &quot;7bit slave address + R/W bit &quot; so please ensure that you&#39;ve followed the format correctly.</p> <p>(2) Check the whether the slave is producing a ACK (low) after the 8bit data has been sent using a &quot;<strong>CRO</strong>&quot; . If it shows that a NACK (high) , I suppose that there is a issue with your sensor module&#39;s hardware</p> <p>Regards HP</p><div style="clear:both;"></div>