
Serial Communication
151
Specifications in this manual are tentative and subject to change
Rev. E
MITSUBISHI MICROCOMPUTERS
M30245 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Function
STSPSEL=0
STSPSEL=1
SCL, SDA output
Output of S I/O control circuit
Output of start/stop condition control
circuit
Start/stop condition interrupt factor
Start/stop condition detection
Completion of start/stop condition
generation
Slave mode (CKDIR = 1, STSPSEL = 0)
SCL
SDA
Start condition
detection interrupt
Stop condition
detection interrupt
Master mode (CKDIR = 0, STSPSEL = 1)
SDA
Start condition
detection interrupt
Stop condition
detection interrupt
STPREQ = 1
STAREQ =1
STSPSEL = 0
STSPSEL = 1
STSPSEL = 0
STSPSEL = 1
STSPSEL = 0
UARTi Special Mode Register 4
Bit 0 is the start condition generate bit. When the SCL, SDA output select bit (bit 3 of UiSMR4) is “1” and
this bit is “1”, the start condition is generated.
Bit 1 is the restart condition generate bit. When the SCL, SDA output select bit (bit 3 of UiSMR4) is “1” and
this bit is “1”, the restart condition is generated.
Bit 2 is the stop condition generate bit. When the SCL, SDA output select bit (bit 3 of UiSMR4) is "1" and
this bit is "1", the stop condition is generated.
Bit 3 is SCL, SDA output select bit. Table 1.52 shows the functions that are changed by this bit. Figure
1.110 shows the functions changed by SCL, SDA output select bit.
Bit 4 is ACK data bit. When the SCL, SDA output select bit (bit 3 of UiSMR4) is “0” and the ACK data output
enable bit (bit 5 of UiSMR4) is “1”, the content of ACK data bit is output to SDAi pin.
Bit 5 is ACK data output enable bit. When the SCL, SDA output select bit (bit 3 of UiSMR4) is “0” and this
bit is “1”, the content of ACK data bit is output to SDAi pin.
Bit 6 is SCL output stop bit. When this bit is “1”, SCLi output is stopped at stop condition detection. (High-Z
status).
Bit 7 is SCL wait output bit 3. When this bit is "1", SCLi output is fixed to "L" at the falling edge of the 10th
clock bit. When this bit is "0", SCLi output fixed to "L" is released.
Table 1.52. Functions changed by SCL, SDA output select bit
Figure 1.110. Functions changed by SCL, SDA output select bit