•Mode 1: Serial port operates as an 8-bit UART with a variable baud rate.10-bits are transmitted on TXD or received on RXD. Start bit (always 0), 8 data bits (LSB first), and a stop bit (always 1). For a receive
operation, the stop bit goes into RB8 in SCON.
Baud Rate Clock is variable using Timer 1
overflow or external count input.
•Transmission is initiated by writing data to SBUF, but does not start until the next rollover of the
divide-by-16 counter supplying the
serial port baud rate. Shifted data are outputted
on the TXD line beginning with the start bit.
The transmit interrupt flag (TI) is set as soon as the stop bit appears on TXD.
•Reception is initiated by a 1-to-0 transition on RXD. The divide-by-16 counter is immediately reset to align the counts with the incoming bit stream.