PIC18C858-E/L Microchip Technology, PIC18C858-E/L Datasheet - Page 239

• Manufacturer Part Number: PIC18C858-E/L
• Description: IC MCU OTP 16KX16 CAN 84PLCC
• Manufacturer: Microchip Technology
• Series: PIC® 18Cr

Specifications of PIC18C858-E/L

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: CAN, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 68
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: OTP
• Ram Size: 1.5K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 16x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 84-PLCC
• For Use With: AC164310 - MODULE SKT FOR PM3 84PLCCDVA18XL840 - ADAPTER DEVICE ICE 84PLCCAC174012 - MODULE SKT PROMATEII 84PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Other names: PIC18C858E/L

19.2
A single comparator is shown in Figure 19-2 along with
the relationship between the analog input levels and
the digital output. When the analog input at V
than the analog input V
comparator is a digital low level. When the analog input
at V
of the comparator is a digital high level. The shaded
areas of the output of the comparator in Figure 19-2
represent the uncertainty due to input offsets and
response time.
19.3
An external or internal reference signal may be used
depending on the comparator operating mode. The
analog signal present at V
at V
adjusted accordingly (Figure 19-2).
FIGURE 19-2: SINGLE COMPARATOR
19.3.1
When external voltage references are used, the
comparator module can be configured to have the com-
parators operate from the same, or different reference
sources. However, threshold detector applications may
require the same reference. The reference signal must
be between V
pin of the comparator(s).
19.3.2
The comparator module also allows the selection of an
internally
comparators. Section 20.0 contains a detailed descrip-
tion of the Comparator Voltage Reference Module that
provides this signal. The internal reference signal is
used when comparators are in mode CM<2:0> = 110
(Figure 19-1). In this mode, the internal voltage refer-
ence is applied to the V
Output
V
V
2000 Microchip Technology Inc.
IN
V
IN
V
IN
utput
IN
IN–
IN+
–
+
+ is greater than the analog input V
+, and the digital output of the comparator is
V
V
IN
IN
Comparator Operation
Comparator Reference
EXTERNAL REFERENCE SIGNAL
INTERNAL REFERENCE SIGNAL
+
–
generated
SS
and V
+
–
DD
IN
voltage
, and can be applied to either
+ pin of both comparators.
IN
– is compared to the signal
IN
–, the output of the
reference
Output
IN
–, the output
Advanced Information
IN
for
+ is less
the
19.4
Response time is the minimum time, after selecting a
new reference voltage or input source, before the
comparator output has a valid level. If the internal ref-
erence is changed, the maximum delay of the internal
voltage reference must be considered when using the
comparator outputs. Otherwise the maximum delay of
the comparators should be used (Section 25.0).
19.5
The comparator outputs are read through the CMCON
Register. These bits are read-only. The comparator
outputs may also be directly output to the RF1 and RF2
I/O pins. When enabled, multiplexors in the output path
of the RF1 and RF2 pins will switch and the output of
each pin will be the unsynchronized output of the com-
parator. The uncertainty of each of the comparators is
related to the input offset voltage and the response
time given in the specifications. Figure 19-3 shows the
comparator output block diagram.
The TRISA bits will still function as an output
enable/disable for the RF1 and RF2 pins while in this
mode.
The polarity of the comparator outputs can be changed
using the C2INV and C1INV bits (CMCON<4:5>).
Note 1: When reading the PORT register, all pins
2: Analog levels on any pin defined as a dig-
Comparator Response Time
Comparator Outputs
configured as analog inputs will read as a
‘0’. Pins configured as digital inputs will
convert an analog input, according to the
Schmitt Trigger input specification.
ital input, may cause the input buffer to
consume more current than is specified.
PIC18CXX8
DS30475A-page 239