Datasheet

Section 13 Serial Communication Interface (SCI)
Rev. 3.00 Sep. 28, 2009 Page 317 of 710
REJ09B0384-0300
13.9.8 Notes on Switching from SCK Pins to Port Pins
When SCK pins are switched to port pins after transmission has completed, pins are enabled for
port output after outputting a low pulse of half a cycle as shown in figure 13.38.
SCK/Port
CKE0
CKE1
C/A
TE
Data
1. Transmission end
2. TE = 0
3. C/A = 0
4. Low pulse output
Bit 6
Bit 7
Low pulse of half a cycle
Figure 13.38 Switching from SCK Pins to Port Pins
To prevent the low pulse output that is generated when switching the SCK pins to the port pins,
specify the SCK pins for input (pull up the SCK/port pins externally), and follow the procedure
below with DDR = 1, DR = 1, C/A = 1, CKE1 = 0, CKE1 = 0, and TE = 1.
1. End serial data transmission
2. TE bit = 0
3. CKE1 bit = 1
4. C/A bit = 0 (switch to port output)
5. CKE1 bit = 0