UPD78F9500MA-CAC-A Datasheet, PDF (27/342 Pages) Renesas Technology Corp – 8-Bit Single-Chip Microcontrollers

CHAPTER 2 PIN FUNCTIONS
2.2.2 P32 and P34 (Port 3)
P32 is a 1-bit I/O port. In addition to the function as an I/O port pin, this pin also has a function to input an external
interrupt request signal.
P34 is a 1-bit input-only port. This pin is also used as a RESET pin, and when the power is turned on, this is the
reset function.
For the setting method for pin functions, see CHAPTER 15 OPTION BYTE.
<R>
When P34 in μPD78F920x is used as an input port pin, connect the pull-up resistor.
P32 and P34 can be set to the following operation modes in 1-bit units.
(1) Port mode
P32 functions as a 1-bit I/O port. This pin can be set to the input or output mode by using port mode register 3
(PM3). In addition, an on-chip pull-up resistor can be connected to the port by using pull-up resistor option
register 3 (PU3).
<R>
P34 functions as a 1-bit input-only port. In μPD78F950x, an on-chip pull-up resistor can be connected to the
port by using pull-up resistor option register 3 (PU3).
(2) Control mode
P32 functions as an external interrupt request input pin (INTP1) for which the valid edge (rising edge, falling
edge, or both rising and falling edges) can be specified.
<R>
Caution In μPD78F950x, the P34/RESET pin is pulled up during reset by the reset pin function/power-on
clear circuit.
2.2.3 P40 and P43 (Port 4)
P40 and P43 constitute a 2-bit I/O port. Each bit of this port can be set to the input or output mode by using port
mode register 4 (PM4)^Note. In addition, an on-chip pull-up resistor can be connected to the port by using pull-up
resistor option register 4 (PU4).
Note In μPD78F920x, set PM41, PM42, and PM44 to PM47 to "0" at program initialization.
2.2.4 RESET
This pin inputs an active-low system reset signal.
regardless of the option byte setting.
When the power is turned on, this is the reset function,
<R>
Caution In μPD78F950x, the P34/RESET pin is pulled up during reset by the reset pin function/power-on
clear circuit.
2.2.5 X1 and X2 (μPD78F920x)
These pins connect an oscillator to oscillate the X1 input clock.
X1 and X2 also function as P23/ANI3 and P22/ANI2, respectively. For the setting method for pin functions, see
CHAPTER 15 OPTION BYTE.
Supply an external clock to X1.
Caution The P22/X2/ANI2 and P23/X1/ANI3 pins are pulled down during reset.
User’s Manual U18172EJ3V0UD
25