HD64F3670 Datasheet, PDF (205/305 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

13.5.5 Simultaneous Serial Data Transmission and Reception
Figure 13-14 shows a sample flowchart for simultaneous serial transmit and receive operations.
The following procedure should be used for simultaneous serial data transmit and receive
operations. To switch from transmit mode to simultaneous transmit and receive mode, after
checking that the SCI3 has finished transmission and the TDRE and TEND flags are set to 1, clear
TE to 0. Then simultaneously set TE and RE to 1 with a single instruction. To switch from receive
mode to simultaneous transmit and receive mode, after checking that the SCI3 has finished
reception, clear RE to 0. Then after checking that the RDRF and receive error flags (OER, FER,
and PER) are cleared to 0, simultaneously set TE and RE to 1 with a single instruction.
Rev. 1.0, 03/01, page 181 of 280