After the master-transmitter has sent the first byte of the 10-bit address, the slave-receiversees an I2C interrupt. User software must ensure that for this interrupt, the contents of theData register are ignored and not treated as valid data.21.5.2.2 Master-receiver addresses a slave-transmitterThe transfer direction is changed after the second R/W bit. Up to and includingacknowledge bit A2, the procedure is the same as that described for a master-transmitteraddressing a slave-receiver. After the repeated START condition (Sr), a matching slaveremembers that it was addressed before. This slave then checks whether the first sevenbits of the first byte of the slave address following Sr are the same as they were after theSTART condition (S), and it tests whether the eighth (R/W) bit is 1. If there is a match,the slave considers that it has been addressed as a transmitter and generates acknowledgeA3. The slave-transmitter remains addressed until it receives a STOP condition (P) or arepeated START condition (Sr) followed by a different slave address.After a repeated START condition (Sr), all other slave devices also compare the firstseven bits of the first byte of the slave address with their own addresses and test theeighth (R/W) bit. However, none of them are addressed because R/W = 1 (for 10-bitdevices), or the 11110XX slave address (for 7-bit devices) does not match.Table 21-5. Master-receiver addresses a slave-transmitter with a 10-bit addressS Slaveaddressfirst 7bits11110 +AD10 +AD9R/W0A1 SlaveaddresssecondbyteAD[8:1]A2 Sr Slaveaddressfirst 7bits11110 +AD10 +AD9R/W1A3 Data A ... Data A PAfter the master-receiver has sent the first byte of the 10-bit address, the slave-transmittersees an I2C interrupt. User software must ensure that for this interrupt, the contents of theData register are ignored and not treated as valid data.21.5.3 Address matchingAll received addresses can be requested in 7-bit or 10-bit address format.Chapter 21 Inter-Integrated Circuit (I2C)MC9S08SU16 Reference Manual, Rev. 5, 4/2017NXP Semiconductors 383
