Renesas rl78 User Manual

 

RL78/G1A 

 

CHAPTER  4   PORT  FUNCTIONS 

R01UH0305EJ0200  Rev.2.00 

 

 

119  

Jul 04, 2013 

Output Settings of Unused Alternate Function 

Output Function of Used Pin 

Output Function for Port

Output Function for SAU 

Output Function for other than SAU 

Output function for port 

− 

Output is high (1) 

Output is low (0) 

Output function for SAU 

High (1) 

− 

Output is low (0) 

Output function for other than 

SAU 

Low (0) 

Output is high (1) 

Output is low (0)

 

 

Note  Since more than one output function other than SAU may be assigned to a single pin, the output of an unused 

alternate function must be set to low level (0).  For details on the setting method, see 4.5.2  Register settings 

for alternate function whose output function is not used. 

 

When the output of an alternate function of the pin is not used, the following settings should be made.  Note that when 

the peripheral I/O redirection function is the target, the output can be switched to another pin by setting the peripheral I/O 

redirection register (PIOR).  This allows usage of the port function or other alternate function assigned to the target pin. 

 

(1)  SOp = 1, TxDq = 1 (settings when the serial output (SOp/TxDq) of SAU is not used) 

When the serial output (SOp/TxDq) is not used, such as, a case in which only the serial input of SAU is used, set the 

bit in serial output enable register m (SOEm) which corresponds to the unused output to 0 (output disabled) and set 

the SOmn bit in serial output register m (SOm) to 1 (high).  These are the same settings as the initial state. 

 

(2)  SCKp = 1, SDAr = 1, SCLr = 1 (settings when channel n in SAU is not used) 

When SAU is not used, set bit n (SEmn) in serial channel enable status register m (SEm) to 0 (operation stopped 

state), set the bit in serial output enable register m (SOEm) which corresponds to the unused output to 0 (output 

disabled), and set the SOmn and CKOmn bits in serial output register m (SOm) to 1 (high).  These are the same 

settings as the initial state. 

 

(3)  TOmn = 0 (settings when the output of channel n in TAU is not used) 

When the TOmn output of TAU is not used, set the bit in timer output enable register 0 (TOE0) which corresponds to 

the unused output to 0 (output disabled) and set the bit in timer output register 0 (TO0) to 0 (low).  These are the 

same settings as the initial state. 

 

(4)  SDAAn = 0, SCLAn = 0 (setting when IICA is not used) 

When IICA is not used, set the IICEn bit in IICA control register n0 (IICCTLn0) to 0 (operation stopped).  This is the 

same setting as the initial state. 

 

(5)  PCLBUZn = 0 (setting when clock/buzzer output is not used) 

When the clock/buzzer output is not used, set the PCLOEn bit in clock output select register n (CKSn) to 0 (output 

disabled).  This is the same setting as the initial state. 

 

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