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#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
pin
PP
If fluctuations in the Flash programming voltage V
the V
and V
pins to suppress fluctuations within V
SS
PP
the V
pin as possible and use a sufficiently thick wiring pattern that allows current of several tens
PP
of mA to flow.
Power supply circuit
Sudden power supply fluctuations due to noise will cause malfunctions. Consider the following issues.
Connections from the power supply to the V
(1)
shortest, thickest patterns possible.
If a bypass capacitor is connected between V
(2)
V
pins should be as short as possible.
SS
Bypass capacitor connection example
C
PW1
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.
26-4
PP
PP
V
pin connection example
PP
Pin
V
PP
V
SS
C
VPP
and V
DD
DD
V
V
DD
DD
V
V
SS
SS
C
PW1
Seiko Epson Corporation
is large, connect a capacitor C
± 1 V. The C
should be placed as close to
VPP
Pin
V
PP
V
SS
C
VPP
pins should be implemented via the
SS
and V
, connections between the V
SS
Prohibited pattern
OSC1
OSC2
Large current signal line
High-speed signal line
S1C31D50 TECHNICAL MANUAL
between
VPP
and
DD
(Rev. 1.00)
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