UPD78F9502MA-CAC-A NEC, UPD78F9502MA-CAC-A Datasheet - Page 54

• Manufacturer Part Number: UPD78F9502MA-CAC-A
• Description: 8BIT MCU, 4K FLASH, 128B RAM, SMD
• Manufacturer: NEC

Specifications of UPD78F9502MA-CAC-A

• Controller Family/series: UPD78F
• No. Of I/o's: 8
• Ram Memory Size: 128Byte
• Cpu Speed: 10MHz
• No. Of Timers: 2
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 4KB
• Oscillator Type: External, Internal

4.2.3
port mode register 4 (PM4). When the P40 and P43 pins are used as an input port, an on-chip pull-up resistor can be
connected in 1-bit units by using pull-up resistor option register 4 (PU4).
54
Caution Because the P34 pin functions alternately as the RESET pin, if it is used as an input port pin, the
Port 4 is a 2-bit I/O port with an output latch. Each bit of this port can be set to the input or output mode by using
Reset signal generation sets port 4 to the input mode.
Figures 4-7 shows the block diagram of port 4.
Port 4
RD:
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 13 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.
Read signal
WR
RD
Reset
PU
Option byte
Figure 4-6. Block Diagram of P34
Preliminary User’s Manual U18681EJ1V0UD
CHAPTER 4 PORT FUNCTIONS
PU34
PU3
V
DD
P-ch
P34/RESET