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Several pins change based on SMi3 bit in SI/Oi control register?

Latest Updated:02/27/2012

Question:

How do the functions of the CLKi pin, SOUTi pin, and SINi pin change according to the setting of the SI/Oi port select bit (SMi3 bit) in the SI/Oi control register (i = 3, 4)?

Answer:

  • If SMi3 bit = "0"
    The CLKi pin, SOUTi pin, and SINi pin function as I/O ports.
  • If SMi3 bit = "1"
    • The function of the CLKi pin changes depending on the SMi6 bit.
      • If the SMi6 bit is "0", the CLKi pin functions as a transfer clock input port.
      • If the SMi6 bit is "1", the CLKi pin functions as a transfer clock output port.
    • The function of the SOUTi pin changes depending on the SMi2 bit.
      • If the SMi2 bit is "0", the SOUTi pin functions as a serial data output port.
      • If the SMi2 bit is "1", the SOUTi pin is high impedance. At this time, it is possible to use it as an input port.
    • The SINi pin functions as a serial data input port. At this time, it is also possible to use it as an I/O port.

In any case, when using as an input port, set the bit in the corresponding port direction register to "0".

Suitable Products
M16C/62A
M16C/62A(M16C/62T)
M16C/62M
M16C/62N
M16C/62N(M3062GF8NFP, M3062GF8NGP)
M16C/62P
M16C/63
M16C/64A
M16C/64C
M16C/65
M16C/65C
M16C/29
M16C/28