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.

© 2024 Microchip Technology, Inc.
Notice: ARM and Cortex are the registered trademarks of ARM Limited in the EU and other countries.
Information contained on this site regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.