Synchronous Operation - Hitachi SH7032 Hardware Manual

Start
1
bit
Serial
0
data
MPB
MPIE
RDRF
RDR
value
RXI request,
(multiprocessor
interrupt)
MPIE = 0
Figure 13.13 Example of SCI Receive Operation (Own ID Matches Data) (8-Bit Data with
13.3.4

Synchronous Operation

In synchronous mode, the SCI transmits and receives data in synchronization with clock pulses.
This mode is suitable for high-speed serial communication.
The SCI transmitter and receiver share the same clock but are otherwise independent, so full
duplex communication is possible. The transmitter and receiver are also double buffered, so
continuous transmitting or receiving is possible by reading or writing data while transmitting or
receiving is in progress.
Figure 13.14 shows the general format in synchronous serial communication.
Data ID2
MPB
D D D 1
0 1 7
ID1
RXI interrupt
handler reads data
in RDR and clears
RDRF to 0
Multiprocessor Bit and One Stop Bit) (cont)
Stop
Start
Data 2
bit
bit
1 0 D D
0 1
ID2
Own ID, so receving
continues, with data
received at each RXI
Stop
1
bit
MPB
Idle (mark)
D 0 1
7
state
Data2
MPIE
bit is again
set to 1
393