PIC12F1840 MICROCHIP [Microchip Technology], PIC12F1840 Datasheet - Page 155

• Manufacturer Part Number: PIC12F1840
• Description: 8-Pin Flash Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

19.7
The C1NCH bit of the CM1CON1 register directs one
of two analog pins to the comparator inverting input.
19.8
The comparator output is indeterminate for a period of
time after the change of an input source or the selection
of a new reference voltage. This period is referred to as
the response time. The response time of the comparator
differs from the settling time of the voltage reference.
Therefore, both of these times must be considered when
determining the total response time to a comparator
input change. See the Comparator and Voltage Refer-
ence Specifications in
cations”
19.9
The C1 comparator can be used as a general purpose
comparator. The output can be brought out to the
C1OUT pin. When the ECCP auto-shutdown is active
it can use the comparator signal. If auto-restart is also
enabled, the comparator can be configured as a
closed loop analog feedback to the ECCP, thereby,
creating an analog controlled PWM.
 2011 Microchip Technology Inc.
Note:
Note:
Comparator Negative Input
Selection
Comparator Response Time
Interaction with ECCP Logic
for more details.
To use C1IN+ and C1INx- pins as analog
input, the appropriate bits must be set in
the ANSEL register and the correspond-
ing TRIS bits must also be set to disable
the output drivers.
When the comparator module is first
initialized the output state is unknown.
Upon initialization, the user should verify
the output state of the comparator prior to
relying on the result, primarily when using
the result in connection with other
peripheral features, such as the ECCP
Auto-Shutdown mode.
Section 30.0 “Electrical Specifi-
Preliminary
19.10 Analog Input Connection
A simplified circuit for an analog input is shown in
Figure
connection with a digital input, they have reverse
biased ESD protection diodes to V
analog input, therefore, must be between V
If the input voltage deviates from this range by more
than 0.6V in either direction, one of the diodes is for-
ward biased and a latch-up may occur.
A maximum source impedance of 10 k is recommended
for the analog sources. Also, any external component
connected to an analog input pin, such as a capacitor or
a Zener diode, should have very little leakage current to
minimize inaccuracies introduced.
Note 1: When reading a PORT register, all pins
19-3. Since the analog input pins share their
2: Analog levels on any pin defined as a
Considerations
configured as analog inputs will read as a
‘0’. Pins configured as digital inputs will
convert as an analog input, according to
the input specification.
digital input, may cause the input buffer to
consume more current than is specified.
PIC12F/LF1840
DS41441A-page 155
DD
and V
SS
and V
SS
. The
DD
.