
102
2. APPLICAT ION
MITSUBISHI MICROCOMPUTER
3819 Group
2.3 Serial I/O
3819 Group USER’S MANUAL
The communication is performed according to the timing shown below. In the slave unit, when a synchronizing clock
is not input within a certain time (heading adjustive time), the next clock input is processed as the beginning (heading)
of a block.
When a clock is input again after one block (8 byte) is received, the clock is ignored.
Figure 2.3.25 shows a setting of related registers.
Fig. 2.3.24 Timing chart [Cyclic transmission or reception of block data between microcomputers]
Fig. 2.3.25 Setting of related registers
[Cyclic transmission or reception of block data between microcomputers]
D
0
Byte cycle
Block transmission period
Block transmission cycle
D
1
D
2
D
7
D
0
Interval between blocks
Processing for heading adjustment
Heading adjustive time
Not be effected by
external clock
Not use the S
RDY1
signal
output function
SIO1CON
Serial I/O 1 control register (Address:19
16
)
0
0
0
1
1
0
1
0
Internal synchronous
clock : f(X
IN
)/32
Use the Serial I/O 1
Not use the S
RDY1
signal
output function
LSB first
Internal clock
CMOS output
SIO1CON
Serial I/O 1 control register (Address:19
16
)
0
0
0
1
0
Use the Serial I/O 1
LSB first
External clock
CMOS output
Master unit
Slave unit
SIOAC
Serial I/O automatic transfer control register (Address:1A
16
)
0
Serial I/O ordinary mode
When an automatic transfer function
is not used, the S
CLK11
is used as an
I/O pin for a synchronizing clock (the
S
CLK12
is not selected).
Note :
[When using the Serial I/O 1]