PD17P709A_15 Datasheet, PDF (23/38 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLER WITH DEDICATED HARDWARE FOR DIGITAL TUNING SYSTEM

µPD17P709A
1.5 Cautions on Using CE, INT0 to INT4, and RESET Pins (Only in Normal Operation Mode)
The CE, INT0 to INT4, and RESET pins have a function to set a test mode in which the internal operations
of the µPD17P709A are tested (IC test), in addition to the functions listed in 1.1 Pin Function List.
When a voltage exceeding VDD is applied to any of these pins, the device is set in the test mode. If a noise
exceeding VDD is superimposed during normal operation, therefore, the test mode is set by mistake, affecting
the normal operation.
Especially if the wiring length of pins is too long, noise is superimposed on these pins. In consequence, the
above problem occurs.
Therefore, keep the wiring length as short as possible to prevent noise from being superimposed. If
superimposition of noise is unavoidable, connect an external component as illustrated below to suppress the
noise.
• Connect a diode with a low VF
between the pin and VDD.
VDD
• Connect a capacitor between the pin and
VDD.
VDD
Diode with
low VF
VDD
VDD
CE, INT0 to INT4, RESET
CE, INT0 to INT4, RESET
1.6 Cautions on Using TEST Pin (Only in Normal Operation Mode)
When VDD is applied to the TEST pin, the device is set in the test mode or program memory write/verify mode.
Therefore, be sure to keep the wiring length of this pin as short as possible, and directly connect it to the GND
pin.
If the wiring length between the TEST pin and GND pin is too long, or if external noise is superimposed on
the TEST pin, generating a potential difference between the TEST pin and GND pin, your program may not run
normally.
GND TEST
Short
Data Sheet U15723EJ1V0DS
21