Hi, My problem is I will communicat with the LPC2148 per I2C bus, the lpc2148 is only used on slave transmitt/receive modes. The datastream which is send to the lpc2148 is: first byte is a function id, the second and third are the lenght of following message without the last two bytes, then I send some databytes, after this i send a Checksum, the checksum is an XOR from all bytes without the checksum and the slave address. If the master sends after the checksum one byte instead of a stop condition my programm should compare the received checksum and the claculated, if they not the same i have to send a NACK(not acknoledge) and then the master sends the stop condition.
My problem is that the lpc2148 dont send the NACK. Can anyone help me?