7906 datasheet(502/531 Pages) RENESAS

502 / 531 page

APPENDIX

Appendix 7. Countermeasure against noise

7906 Group User’s Manual Rev.2.0

20-97

(3)

Wiring for MD0 and MD1 pins

Connect MD0 and MD1 pins to the Vss pin (or Vcc pin) with the shortest possible wiring.

Reason:

The processor mode of the

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.

Noise

MD0

Vss

M37906

Vss

M37906

Acceptable

Not Acceptable

MD1

MD0

MD1

Fig. 4 Wiring for MD0 and MD1 pins

2. Connection of bypass capacitor between Vss and Vcc lines

Connect an approximate 0.1

µF bypass capacitor as follows:

q Connect a bypass capacitor between the Vss and Vcc pins, at equal lengths.

q The wiring connecting the bypass capacitor between the Vss and Vcc pins should be as short as

possible.

q Use thicker wiring for the Vss and Vcc lines than that for the other signal lines.

Fig. 5 Bypass capacitor between Vss and Vcc lines

Bypass capacitor

Vcc

Vss

M37906

Wiring pattern

7906 Datasheet(PDF) 502 Page - Renesas Technology Corp

7906 Datasheet(HTML) 502 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL