Specifications

mikroElektronika | Free Online Book | PIC Microcontrollers | Chapter 6: Serial Communication Modules
Fig. 6-5 Receiving 9-bit Data
Address Detection
When the ADDEN bit of the RCSTAregister is set, the EUSART module is able to receive only 9-bit data, whereas all 8-bit
data will be ignored. Although it seems like a restriction, such modes enable serial communication between several
microcontrollers. The principle of operation is simple. The master device sends 9-bit data which represents the address of
one microcontroller. All slave microcontrollers sharing the same transmission line, receive this data. Of course, each of
them must have the ADDEN bit set because it enables address detection.
Upon receiving this data each slave checks if that address matches its own. Software, in which address match occurs,
must disable address detection by clearing its ADDEN bit. The master device keeps on sending 8-bit data. All data passing
through the transmission line will be received by "recognized" EUSART module only. Upon receiving the last byte, the slave
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