SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The TXx_EMPTY event is activated when a channel is enabled and its MCSPI_TXx register is empty (transient event). Enabling a channel automatically triggers this event, except in master receive-only mode (see Section 26.4.4.3.4, Master Receive-Only Mode). When the FIFO buffer is enabled (the MCSPI_CHxCONF[27] FFEW bit is set to 1), the MCSPI_IRQSTATUS TXx_EMPTY bit is set as soon as there is enough space in the buffer to write a number of bytes defined by the MCSPI_XFERLEVEL[5:0] AEL bit field.
The MCSPI_TXx register must be loaded with data to remove the source of the interrupt; the MCSPI_IRQSTATUS TXx_EMPTY interrupt status bit must be cleared for interrupt line deassertion (if the event is enabled as the interrupt source).
When FIFO is enabled, no new TXx_EMPTY event is asserted as long as the MPU has not performed the number of writes into the MCSPI_TXx register defined by the MCSPI_XFERLEVEL[5:0] AEL bit field. The MPU must perform the correct number of writes.