m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 536

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

Fig. 5 Bypass capacitor between Vss and Vcc lines
2. Connection of bypass capacitor between Vss and Vcc lines
Connect an approximate 0.1 µ F bypass capacitor as follows:
(3) Wiring for MD0 and MD1 pins
Use thicker wiring for the Vss and Vcc lines than that for the other signal lines.
Connect a bypass capacitor between the Vss and Vcc pins, at equal lengths.
The wiring connecting the bypass capacitor between the Vss and Vcc pins should be as short as
possible.
Connect MD0 and MD1 pins to the Vss pin (or Vcc pin) with the shortest possible wiring.
Reason:
T h e p r o c e s s o r m o d e o f t h e
microcomputer is influenced by a
potential at the MD0 and MD1 pins
when the MD0 and MD1 pins and
the Vss pin (or Vcc pin) are
connected.
If the noise causes a potential
difference between the MD0 and
MD1 pins and the Vss pin (or Vcc
pin), the processor mode may
become unstable. This may cause
a microcomputer malfunction or
a program runaway.
Wiring pattern
7905 Group User’s Manual Rev.1.0
Vss
M37905
Bypass capacitor
Appendix 7. Countermeasure against noise
Fig. 4 Wiring for MD0 and MD1 pins
Vcc
Wiring pattern
Not Acceptable
M37905
MD1
MD0
Vss
Noise
Acceptable
APPENDIX
M37905
MD1
MD0
Vss
20-105