upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 70

• Manufacturer Part Number: upd78f0730
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

4.2.3 Port 3
using port mode register 3 (PM3). When the P30 to P33 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 3 (PU3).
70
Port 3 is a 4-bit I/O port with an output latch. Port 3 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 and timer I/O.
Reset signal generation sets port 3 to input mode.
Figures 4-10 and 4-11 show block diagrams of port 3.
Cautions 1. Be sure to pull the P31 pin down before a reset release to prevent malfunction.
Remark The P31 and P32 pins of the
WR
WR
WR
P3:
PU3:
PM3:
RD:
WR××: Write signal
RD
PORT
PU
PM
OCD1B) when the on-chip debug function is used. For details, see CHAPTER 20 ON-CHIP DEBUG
FUNCTION.
2. When writing the flash memory with a flash memory programmer, connect P31/INTP2/OCD1A
as follows.
• P31/INTP2/OCD1A: Connect to EV
The above connection is not necessary when writing the flash memory by means of self
programming.
Port register 3
Pull-up resistor option register 3
Port mode register 3
Read signal
PM30 to PM32
PU30 to PU32
(P30 to P32)
Output latch
Alternate
function
PM3
PU3
P3
Figure 4-10. Block Diagram of P30 to P32
Preliminary User’s Manual U19014EJ1V0UD
CHAPTER 4 PORT FUNCTIONS
µ
PD78F0730 can be used as on-chip debug mode setting pins (OCD1A,
SS
via a resistor (10 kΩ: recommended).
EV
DD
P-ch
P30/INTP1,
P31/INTP2/OCD1A,
P32/INTP3/OCD1B