Datasheet

Clear

UTXIEx

Clear

Character Moved From

Buffer to Shift Register

Interrupt Service Requested

SWRST

Data moved to UxTXBUF

UTXIFGx

IRQA

PUC or SWRST

Set

SYNC = 1

USART Operation: SPI Mode

www.ti.com

19.2.6 SPI Interrupts

The USART has one interrupt vector for transmission and one interrupt vector for reception.

19.2.6.1 SPI Transmit Interrupt Operation

The UTXIFGx interrupt flag is set by the transmitter to indicate that UxTXBUF is ready to accept another

character. An interrupt request is generated if UTXIEx and GIE are also set. UTXIFGx is automatically

reset if the interrupt request is serviced or if a character is written to UxTXBUF.

UTXIFGx is set after a PUC or when SWRST = 1. UTXIEx is reset after a PUC or when SWRST = 1. The

operation is shown is Figure 19-10.

Figure 19-10. Transmit Interrupt Operation

NOTE: Writing to UxTXBUF in SPI Mode

Data written to UxTXBUF when UTXIFGx = 0 and USPIEx = 1 may result in erroneous data

transmission.

504

USART Peripheral Interface, SPI Mode SLAU144J–December 2004–Revised July 2013

Submit Documentation Feedback