HD64F2145 Datasheet, PDF (420/829 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

15.6.5 Simultaneous Serial Data Transmission and Reception (Clocked Synchronous
Mode)
Figure 15.20 shows a sample flowchart for simultaneous serial transmit and receive operations.
After initializing the SCI, 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, check that the SCI has finished transmission and the TDRE and TEND flags in SSR
are set to 1, clear the TE bit in SCR to 0, and then set the TE and RE bits to 1 simultaneously with
a single instruction. To switch from receive mode to simultaneous transmit and receive mode,
check that the SCI has finished reception, and clear the RE bit to 0. Then after checking that the
RDRF bit in SSR and receive error flags (ORER, FER, and PER) are cleared to 0, set the TE and
RE bits to 1 simultaneously with a single instruction.
Rev. 2.0, 08/02, page 380 of 788