UPD78F9500MA-CAC-A Datasheet, PDF (67/342 Pages) Renesas Technology Corp – 8-Bit Single-Chip Microcontrollers

CHAPTER 4 PORT FUNCTIONS
Figure 4-9. Block Diagram of P34 (μPD78F920x)
RD
Reset
Option
byte
P34/RESET
RD: Read signal
Caution Because the P34 pin functions alternately as the RESET pin, if it is used as an input port pin, the
function to input an external reset signal to the RESET pin cannot be used. The function of the
port is selected by the option byte. For details, refer to CHAPTER 15 OPTION BYTE.
Also, since the option byte is referenced after the reset release, if low level is input to the RESET
pin before the referencing, then the reset state is not released. When it is used as an input port
pin, connect the pull-up resistor.
<R>
Figure 4-10. Block Diagram of P34 (μPD78F950x)
WRPU
PU3
PU34
VDD
P-ch
RD
Reset
P34/RESET
RD: Read signal
Option byte
Caution Because the P34 pin functions alternately as the RESET pin, if it is used as an input port pin, the
function to input an external reset signal to the RESET pin cannot be used. The function of the
port is selected by the option byte. For details, refer to CHAPTER 15 OPTION BYTE.
Also, since the option byte is referenced after the reset release, if low level is input to the RESET
pin before the referencing, then the reset state is not released. When it is used as an input port
pin, connect an on-chip pull-up resistor by using bit 4 (PU34) of pull-up resistor option register 3
(PU3).
User’s Manual U18172EJ3V0UD
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