SLAU723A October 2017 – October 2018 MSP432E401Y , MSP432E411Y
Both the master and the slave module have the capability to access two 8-byte FIFOs that can be used in conjunction with the µDMA for fast transfer of data. The transmit (TX) FIFO and receive (RX) FIFO can be independently assigned to either the I2C master or I2C slave. Thus, the following FIFO assignments are allowed:
In most cases, both FIFOs will be assigned to either the master or the slave. The FIFO assignment is configured by programming the TXASGNMT and RXASGNMT bit in the I2C FIFO Control (I2CFIFOCTL) register.
Each FIFO has a programmable threshold point which indicates when the FIFO service interrupt should be generated. Additionally, a FIFO receive full and transmit empty interrupt can be enabled in the Interrupt Mask (I2CxIMR) registers of both the master and slave. Note that if we clear the TXFERIS interrupt (by setting the TXFEIC bit) when the TX FIFO is empty, the TXFERIS interrupt does not reassert even though the TX FIFO remains empty in this situation.
When a FIFO is not assigned to a master or a slave module, the FIFO interrupt and status signals to the module are forced to a state that indicates the FIFO is empty. For example, if the TX FIFO is assigned to the master module, the status signals to the slave transmit interface indicates that the FIFO is empty.
NOTE
The FIFOs must be empty when reassigning the FIFOs for proper functionality