upd78f0134hgka1-9et-a Renesas Electronics Corporation., upd78f0134hgka1-9et-a Datasheet - Page 96

• Manufacturer Part Number: upd78f0134hgka1-9et-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

4.2.4 Port 3
using port mode register 3 (PM3). When 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).
96
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 input sets port 3 to input mode.
Figures 4-12 and 4-13 show block diagrams of port 3.
Caution In the PD78F0138HD, be sure to pull the P31 pin down after reset to prevent malfunction.
Remark P31/INTP2 and P32/INTP3 of the PD78F0138HD can be used for on-chip debug mode setting when
PU3:
PM3:
RD:
WR
WR
WR
WR
RD
PORT
the on-chip debug function is used. For details, refer to CHAPTER 27 ON-CHIP DEBUG FUNCTION
( PD78F0138HD ONLY).
PU
PM
: Write signal
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
Figure 4-12. Block Diagram of P30 to P32
CHAPTER 4 PORT FUNCTIONS
User’s Manual U16899EJ3V0UD
EV
DD
P-ch
P30/INTP1 to
P32/INTP3