https://community.nxp.com/t5/LPC-Microcontrollers/LPC824-I2C-master-not-receiving-two-bytes-in-a-row/m-p/1659831#M52795 <P>Hi all,</P><P>I would like to use the LPC824 I2C in master mode to receive two bytes consecutively.</P><P>It all works correctly until the LPC824 (the master) receives the first byte (LPC send slave address and the slave acknowledges, the LPC send the register address to be read and the slave ack and then the slave sends the first byte). Then if the master had sent an ACK the slave would have sent the next byte but the LPC824 is not sending the ACK and everything stops.</P><P>What should I do to make the LPC824 to send an ACK after receiving the first byte?&nbsp;</P><P>Looking at the waveforms I have seen that when the master is receiving the first byte, it only produces 8 clock pulses, so it is missing the clock pulse for the ACK bit.</P><P>Green: slave register address acknoledged</P><P>gray: first byte (with the missing ack from the master)</P><P>yellow: master sends NACK and a stop after a while</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="tomato_0-1685441407584.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/225406i9FF0DB26DF366A2D/image-size/medium?v=v2&amp;px=400" role="button" title="tomato_0-1685441407584.png" alt="tomato_0-1685441407584.png" /></span></P><P>Do you know what I could do to solve this issue?</P> Tue, 30 May 2023 10:16:31 GMT tomato 2023-05-30T10:16:31Z https://community.nxp.com/t5/LPC-Microcontrollers/LPC824-I2C-master-not-receiving-two-bytes-in-a-row/m-p/1659831#M52795 <P>Hi all,</P><P>I would like to use the LPC824 I2C in master mode to receive two bytes consecutively.</P><P>It all works correctly until the LPC824 (the master) receives the first byte (LPC send slave address and the slave acknowledges, the LPC send the register address to be read and the slave ack and then the slave sends the first byte). Then if the master had sent an ACK the slave would have sent the next byte but the LPC824 is not sending the ACK and everything stops.</P><P>What should I do to make the LPC824 to send an ACK after receiving the first byte?&nbsp;</P><P>Looking at the waveforms I have seen that when the master is receiving the first byte, it only produces 8 clock pulses, so it is missing the clock pulse for the ACK bit.</P><P>Green: slave register address acknoledged</P><P>gray: first byte (with the missing ack from the master)</P><P>yellow: master sends NACK and a stop after a while</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="tomato_0-1685441407584.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/225406i9FF0DB26DF366A2D/image-size/medium?v=v2&amp;px=400" role="button" title="tomato_0-1685441407584.png" alt="tomato_0-1685441407584.png" /></span></P><P>Do you know what I could do to solve this issue?</P> Tue, 30 May 2023 10:16:31 GMT https://community.nxp.com/t5/LPC-Microcontrollers/LPC824-I2C-master-not-receiving-two-bytes-in-a-row/m-p/1659831#M52795 tomato 2023-05-30T10:16:31Z https://community.nxp.com/t5/LPC-Microcontrollers/LPC824-I2C-master-not-receiving-two-bytes-in-a-row/m-p/1662248#M52833 <P>We have i2c examples in the SDK with the master and slave function, when you run these examples on the two boards, does the same thing happen?</P> Fri, 02 Jun 2023 01:33:33 GMT https://community.nxp.com/t5/LPC-Microcontrollers/LPC824-I2C-master-not-receiving-two-bytes-in-a-row/m-p/1662248#M52833 CarlosGarabito 2023-06-02T01:33:33Z