Operation In Synchronous Mode - Hitachi H8/3637 Hardware Manual

Figure 10.11 shows a typical SCI3 data receive operation in asynchronous mode.
Start
bit
Serial
1 0 D0
data
RDRF
FER
SCI3 operation
User processing
Figure 10.11 Typical Receive Operation in Asynchronous Mode
10.3.5

Operation in Synchronous Mode

In synchronous mode, data is sent or received in synchronization with clock pulses. This mode is
suited to high-speed serial communication.
SCI3 consists of independent transmit and receive modules, so full duplex communication is
possible, sharing the same clock between both modules. Both the transmit and receive modules
have a double-buffer configuration. This allows data to be written during a transmit operation so
that data can be transmitted continuously, and enables data to be read during a receive operation so
that data can be received continuously.
252
Receive Parity Stop
data bit bit
D1 D7 0/1
1 frame
RXI request
(8-Bit Data, Parity Bit Added, and 1 Stop Bit)
Start Receive
bit data
1 0 D0 D1
1 frame
RDRF cleared
to 0
Read RDR data
Parity Stop Mark
bit bit (idle state)
D7 0/1 0 1
Detects stop bit = 0
ERI request due
to framing error
Framing error
handling