26-4
Seiko Epson Corporation
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
#RESET pin
Components such as a switch and resistor connected to the #RESET pin should have the shortest
connections possible to prevent noise-induced resets.
V
PP
pin
If fluctuations in the Flash programming voltage V
PP
is large, connect a capacitor C
VPP
between
the V
SS
and V
PP
pins to suppress fluctuations within V
PP
± 1 V. The C
VPP
should be placed as close to
the V
PP
pin as possible and use a sufficiently thick wiring pattern that allows current of several tens
of mA to flow.
Power supply circuit
Sudden power supply fluctuations due to noise will cause malfunctions. Consider the following issues.
(1)
Connections from the power supply to the V
DD
and V
SS
pins should be implemented via the
shortest, thickest patterns possible.
(2)
If a bypass capacitor is connected between V
DD
and V
SS
, connections between the V
DD
and
V
SS
pins should be as short as possible.
Signal line location
•
To prevent electromagnetically-induced noise arising from mutual induction, large-current
signal lines should not be positioned close to pins susceptible to noise, such as oscillator and
analog measurement pins.
•
Locating signal lines in parallel over significant distances or crossing signal lines operating at
high speed will cause malfunctions due to noise generated by mutual interference.
•
The SEG/COM lines and voltage boost/reduce capacitor drive lines are more likely to generate
noise, therefore keep a distance between the lines and pins susceptible to noise.
Pin
V
PP
pin connection example
C
VPP
V
PP
V
SS
Pin
C
VPP
V
PP
V
SS
C
PW1
V
DD
V
SS
C
PW1
V
DD
V
SS
Bypass capacitor connection example
Prohibited pattern
OSC1
OSC2
Large current signal line
High-speed signal line
Summary of Contents for S1C31D50
Page 461: ...25 1 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 25 Package TQFP12 48PIN ...
Page 462: ...25 2 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 QFP13 64PIN ...
Page 463: ...25 3 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 TQFP14 80PIN ...
Page 464: ...25 4 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 QFP15 100PIN ...