UPD78F0138 NEC, UPD78F0138 Datasheet - Page 111

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

4.2.11 Port 14
using port mode register 14 (PM14). When the P140 and P141 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 14 (PU14).
Port 14 is a 2-bit I/O port with an output latch. Port 14 can be set to the input mode or output mode in 1-bit units
This port can also be used for external interrupt request input, buzzer output, and clock output.
RESET input sets port 14 to input mode.
Figure 4-20 shows a block diagram of port 14.
WR
WR
WR
PU14:
PM14:
RD:
WR××: Write signal
RD
PORT
PU
PM
Read signal
Pull-up resistor option register 14
Port mode register 14
PM140, PM141
PU140, PU141
(P140, P141)
Output latch
Alternate
Alternate
function
function
PM14
PU14
Figure 4-20. Block Diagram of P140 and P141
CHAPTER 4 PORT FUNCTIONS
User’s Manual U16228EJ2V0UD
EV
DD
P-ch
P140/PCL/INTP6,
P141/BUZ/INTP7
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