I²C Not Able to Write to SSPBUF

When using the MSSP module in I²C mode, sometimes the application is not able to write data to SSPBUF. Why is this?

A write-collision occurs when an attempt is made to write to SSPBUF before the previous SSBUF write has completed. If a write collision occurs then the WCOL status bit is set to 1, the write to SSPBUF will fail. The MSSP interrupt flag can be used to check when the previous write has completed and when it is safe to write the next data to SSPBUF.

Debug Tip: Toggle a spare I/O pin around the SSPBUF write. View this pin on an oscilloscope alongside the I²C pins to verify if the SSBUF write is not being attempted while the previous byte is still being clocked out.

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