MB95710M Series
MB95770M Series
Document Number: 002-09307 Rev. *D Page 118 of 172
19.9.4 Port E operations
• Operation as an output port
• A pin becomes an output port if the bit in the DDRE register corresponding to that pin is set to “1”.
• For a pin shared with other peripheral functions, disable the output of such peripheral functions.
• When a pin is used as an output port, it outputs the value of the PDRE register to external pins.
• If data is written to the PDRE register, the value is stored in the output latch and is output to the pin set as an output
port as it is.
• Reading the PDRE register returns the PDRE register value.
• To use a pin shared with the LCDC as an output port, set a corresponding function select bit in the LCDC enable
register 4 (LCDCE4:SEG[15:14]) or in the LCDC enable register 5 (LCDCE5:SEG[21:16]) to “0” to select the gen-
eral-purpose I/O port function, and then set the port input control bit in the LCDC enable register 1 (LC-
DCE1:PICTL) to “1”.
• Operation as an input port
• A pin becomes an input port if the bit in the DDRE register corresponding to that pin is set to “0”.
• For a pin shared with other peripheral functions, disable the output of such peripheral functions.
• If data is written to the PDRE register, the value is stored in the output latch but is not output to the pin set as an
input port.
• Reading the PDRE register returns the pin value. However, if the read-modify-write (RMW) type of instruction is
used to read the PDRE register, the PDRE register value is returned.
• To use a pin shared with the LCDC as an input port, set a corresponding function select bit in the LCDC enable
register 4 (LCDCE4:SEG[15:14]) or in the LCDC enable register 5 (LCDCE5:SEG[21:16]) to “0” to select the gen-
eral-purpose I/O port function, and then set the PICTL bit in the LCDCE1 register to “1”.
• Operation as a peripheral function output pin
• A pin becomes a peripheral function output pin if the peripheral output function is enabled by setting the output
enable bit of a peripheral function corresponding to that pin.
• The pin value can be read from the PDRE register even if the peripheral function output is enabled. Therefore, the
output value of a peripheral function can be read by the read operation on the PDRE register. However, if the read-
modify-write (RMW) type of instruction is used to read the PDRE register, the PDRE register value is returned.
• Operation as a peripheral function input pin
• To set a pin as an input port, set the bit in the DDRE register corresponding to the input pin of a peripheral function
to “0”.
• Reading the PDRE register returns the pin value, regardless of whether the peripheral function uses that pin as its
input pin. However, if the read-modify-write (RMW) type of instruction is used to read the PDRE register, the PDRE
register value is returned.
• Operation as an LCDC segment output pin
• Set the bit in the DDRE register corresponding to an LCDC segment output pin to “0”.
• To use a pin shared with a general-purpose I/O port as an LCDC segment output pin, set a corresponding function
select bit in the LCDC enable register 4 (LCDCE4:SEG[15:14]) or in the LCDC enable register 5 (LC-
DCE5:SEG[21:16]) to “1” to select the LCDC segment output function, and then set the PICTL bit in the LCDCE1
register to “1”.
• Operation at reset
If the CPU is reset, all bits in the DDRE register are initialized to “0” and port input is enabled.
• Operation in stop mode and watch mode
• If the pin state setting bit in the standby control register (STBC:SPL) is set to “1” and the device transits to stop
mode or watch mode, the pin is compulsorily made to enter the high impedance state regardless of the DDRE reg-
ister value. The input of that pin is locked to “L” level and blocked in order to prevent leaks due to input open.
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