
102
2. APPLICATION
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]
D0
Byte cycle
Block transmission period
Block transmission cycle
D1
D2
D7
D0
Interval between blocks
Processing for heading adjustment
Heading adjustive time
Not be effected by
external clock
Not use the SRDY1 signal
output function
SIO1CON
Serial I/O 1 control register (Address:1916)
Internal synchronous
clock : f(XIN)/32
Use the Serial I/O 1
Not use the SRDY1 signal
output function
LSB first
Internal clock
0
110
1
SIO1CON
Serial I/O 1 control register (Address:1916)
Use the Serial I/O 1
LSB first
External clock
0
01
Master unit
Slave unit
SIOAC
Serial I/O automatic transfer control register (Address:1A16)
Serial I/O ordinary mode
0
When an automatic transfer function
is not used, the S CLK11 is used as an
I/O pin for a synchronizing clock (the
SCLK12 is not selected).
Note :
[When using the Serial I/O 1]
0
CMOS output
0
CMOS output