Datasheet
Section 9 I/O Ports 
    Rev. 3.00 Mar. 15, 2006 Page 119 of 526 
   REJ09B0060-0300 
•  P22/TXD pin 
Register PMR1 PCR2   
Bit Name TXD  PCR22 Pin Function 
Setting Value  0  0  P22 input pin 
    1  P22 output pin 
  1  X  TXD output pin 
[Legend]  X: Don't care. 
•  P21/RXD pin 
Register SCR3 PCR2   
Bit Name RE  PCR21 Pin Function 
Setting Value  0  0  P21 input pin 
    1  P21 output pin 
  1  X  RXD input pin 
[Legend]  X: Don't care. 
•  P20/SCK3 pin 
Register SCR3 SMR PCR2  
Bit Name CKE1 CKE0  COM  PCR20 Pin Function 
Setting Value  0  0  0  0  P20 input pin 
      1 P20 output pin 
  0  0  1  X  SCK3 output pin 
  0  1  X  X  SCK3 output pin 
  1  X  X  X  SCK3 input pin 
[Legend]  X: Don't care. 










