Introduction and detection of erroneous stop condition in a single UART

A method, comprising, in a universal asynchronous receiver/transmitter (UART), the UART:

• routing contents of a transmission register to a receive register, the transmission register to include information to be transmitted by the UART, the receive register to include information received by the UART;
• modifying a bit inversion register or issuing or a bit inversion signal to cause modified contents to be provided to the receive register, the modified contents to cause a frame error, the bit inversion register or bit inversion signal to cause transmitted or received information to be inverted;
• with a frame error checking circuit, evaluating contents of the receive register for a frame error;
• and
• determining whether the frame error checking circuit detected the frame error.

A microcontroller, comprising:

• a universal asynchronous receiver/transmitter (UART),
• a transmission register to include information to be transmitted by the UART;
• a receive register to include information received by the UART;
• a frame error checking circuit to evaluate contents of the receive register for a frame error;
• and
• control logic to:
• route the contents of the transmission register to the receive register;
• modify a bit inversion register or issue a bit inversion signal to cause modified contents to be provided to the receive register, the modified contents to cause a frame error, the bit inversion register or bit inversion signal to cause transmitted or received information to be inverted;
• and
• determine whether the frame error checking circuit detected the frame error.