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CHAPTER 12 SERIAL INTERFACE
User
’
s Manual U15017EJ2V0UD
12.6 Cautions on Using Serial Interface 2 (SIO2)
(1) When using the P55 to P57 pins as serial pins, set the port 5 mode register (PM5) to input mode (set bits 5
to 7 (PM55 to PM57) of PM5 to 1).
For serial interface 0, 1 (SIO0, SIO1)
When using the SIO0, SIO1, SCK0, and SCK1 pins as output pins, set PM2 and PM6 to output mode (refer
to
CHAPTER 4 Table 4-2
).
If PM5 is set to output mode when using the SO2 and SCK2 pins as output pins, output signals from the
peripheral evaluation chip and CPU evaluation chip conflict during emulation. Consequently, the reliability of
the chip may be degraded.
(2) When using the SO2 and SCK2 pins as output pins when operation is started or stopped, set the pins using
the following procedure.
<1> When operation is started
a.
Set the port 5 mode register (PM5) to input mode (set bits 6 and 7 (PM56 and PM57) of PM5 to 1).
b.
Write 0 to the output latch.
c.
Set bits 0 and 1 (SCL20 and SCL21) of serial operation mode register 2 (CSIM2) to other than
“
0,
0
”
(in the case of the SCK2 pin)
d.
Enable serial operation (set bit 7 of CSIM2 (CSIE2) to 1).
At this time, the output buffer is turned on, and serial data (in case of the SO2 pin) and the serial
clock (in the case of the SCK2 pin) enter a wait state.
<2> When operation is stopped
a.
Disable serial operation (set bit 7 of CSIM2 (CSIE2) to 0).
At this time, the output buffer is turned off and is in input port mode.
b.
Set bits 6 and 7 (PM56 and PM57) of PM5 to 0, 0 to set output mode.