R8C/1A Group, R8C/1B Group
16. Clock Synchronous Serial Interface
Rev.1.30
Dec 08, 2006
Page 189 of 315
REJ09B0252-0130
16.2.5.4
Data Transmission/Reception
Data transmission/reception is an operation combining data transmission and reception, which were described
earlier. Transmission/reception is started by writing data to the SSTDR register.
When the 8th clock rises or the ORER bit is set to 1 (overrun error) while the TDRE bit is set to 1 (data is
transferred from registers SSTDR to SSTRSR), the transmit/receive operation is stopped.
When switching from transmit mode (TE = 1) or receive mode (RE = 1) to transmit/receive mode (Te = RE =
1), set the TE bit to 0 and RE bit to 0 before switching. After confirming that the TEND bit is set to 0 (the
TDRE bit is set to 0 when the last bit of the transmit data is transmitted), the RDRF bit is set to 0 (no data in the
SSRDR register) and the ORER bit is set to 0 (no overrun error), set bits TE and RE to 1.
Figure 16.17 shows a Sample Flowchart of Data Transmission/Reception (Clock Synchronous Communication
Mode).