UPD78F0411GA-GAM-AX Datasheet, PDF (81/564 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 4 PORT FUNCTIONS
4.2.1 Port 1
Port 1 is a 2-bit I/O port with an output latch. Port 1 can be set to the input mode or output mode in 1-bit units
using port mode register 1 (PM1). When the P12 and P13 pins are used as an input port, use of an on-chip pull-up
resistor can be specified in 1-bit units by pull-up resistor option register 1 (PU1).
This port can also be used for key interrupt input and serial interface data I/O.
Reset signal generation sets port 1 to input mode.
Figures 4-2 and 4-3 show block diagrams of port 1.
WRPU
RD
Figure 4-2. Block Diagram of P12
PU1
PU12
Alternate
function
VDD
P-ch
WRPORT
WRPM
P1
Output latch
(P12)
PM1
PM12
P1:
PU1:
PM1:
RD:
WR××:
Port register 1
Pull-up resistor option register 1
Port mode register 1
Read signal
Write signal
P12/RxD0/KR3/<RxD6>
User’s Manual U18698EJ1V0UD
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