SPRUIY4B February 2023 – May 2024 TMS320F2800152-Q1 , TMS320F2800153-Q1 , TMS320F2800154-Q1 , TMS320F2800155 , TMS320F2800155-Q1 , TMS320F2800156-Q1 , TMS320F2800157 , TMS320F2800157-Q1
To use transmit interrupt functionality, SET TX INT bit must be enabled . The transmit ready (TXRDY) flag is set when the SCI transfers the contents of SCITD to the shift register, SCITXSHF. The TXRDY flag indicates that SCITD is ready to be loaded with more data. In addition, the SCI sets the TX EMPTY bit if both the SCITD and SCITXSHF registers are empty. If the SET TX INT bit is set, then a transmit interrupt is generated when the TXRDY flag goes high. Transmit Interrupt is not generated immediately after setting the SET TX INT . Transmit Interrupt is generated only after the first transfer from SCITD to SCITXSHF, that is first data has to be written to SCITD before any interrupt gets generated. To transmit further data, data can be written to SCITD in the transmit Interrupt service routine.
Writing data to the SCITD register clears the TXRDY bit. When this data has been moved to the SCITXSHF register, the TXRDY bit is set again. The interrupt request can be suspended by setting the CLR TX INT bit; however, when the SET TX INT bit is again set to 1, the TXRDY interrupt is asserted again. The transmit interrupt request can be eliminated until the next series of values is written to SCITD, by disabling the transmitter using the TXENA bit, by a software reset SWnRST, or by a device hardware reset.