Fujitsu MB90895 Series Hardware Manual page 488

CHAPTER 15 UART1
Figure 15.6-7 Example of Bidirectional Communication Connect for UART
CPU-1
G
Communication procedure
Communications start at any timing from the transmitting end when transmit data is provided.At the
transmitting end, set transmit data in the serial output data register (SODR1) and set the transmitting enable
bit in the serial control register (SCR1 register bit 8: TXE) to 1 to start transmitting.
gives an example of transferring receive data to the transmitting end to inform the transmitting end of
normal reception.
NO
470
SOT
SIN
Output
SCK
Figure 15.6-8 Flowchart for Bidirectional Communication
(Transmission side)
Start
Opearating mode setting
(either 0 or 2)
Setting 1 byte data to SODR
and communicating
With reception data
YES
Reading reception data
and processing
SOT
SIN
Input
SCK
(Reception side)
Operating mode setting
(synchronized with transmission side)
Data
transmission
With reception data
NO
Reading reception data
and processing
Data
transmission
Transmission of 1byte data
CPU-2
Start
YES