m3819 Renesas Electronics Corporation., m3819 Datasheet - Page 117

• Manufacturer Part Number: m3819
• Description: Mitsubishi 8-bit Single-chip Microcomputer 740 Family / 38000 Series
• Manufacturer: Renesas Electronics Corporation.

2. APPLICATION
Fig. 2.3.26 Control in the master unit
Control procedure :
(1) Control in the master unit
After a setting of the related registers is completed as shown in Figure 2.3.25, in the master unit transmission
or reception of one-byte data is started simply by writing transmission data to the Serial I/O 1 register.
To perform the communication in the timing shown in the specifications, therefore, take the timing into account
and write transmission data. Read out the reception data when the Serial I/O 1 interrupt request bit is set to “1”,
or before the next transmission data is written to the Serial I/O 1 register.
A processing example in the master unit using timer interrupts is shown below.
Interrupt processing routine
executed every 488 s
Write a transmission data
Complete to transmit a block?
Within a block transfer period?
Read a reception data
RTI
Y
N
N
Y
3819 Group USER’S MANUAL
Write the first transmission data
(first byte) in a block
Count a block interval counter
Start a block transfer?
Y
Check the block interval counter and
determine to start of a block transfer.
Generate a certain block interval by
using a timer or other functions.
MITSUBISHI MICROCOMPUTER
N
2.3 Serial I/O
3819 Group
103