PIC18F27J53T-I/SO Microchip Technology, PIC18F27J53T-I/SO Datasheet - Page 436

• Manufacturer Part Number: PIC18F27J53T-I/SO
• Description: 28-pin, USB, 128KB Flash, 4KB RAM, 12 MIPS, 12-bit ADC, NanoWatt XLP 28 SOIC .30
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F27J53T-I/SO

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 48MHz
• Connectivity: I²C, LIN, SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Ram Size: 3.8K x 8
• Voltage - Supply (vcc/vdd): 2.15 V ~ 3.6 V
• Data Converters: A/D 10x10b/12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 3.8 KB
• Interface Type: I2C, SPI, USART
• Maximum Clock Frequency: 48 MHz
• Number Of Programmable I/os: 16
• Number Of Timers: 8
• Operating Supply Voltage: 2.15 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

PIC18F47J53 FAMILY
27.6
A unique feature on board the CTMU module is its
ability to generate system clock, independent output
pulses based on an external capacitor value. This is
accomplished using the internal comparator voltage
reference module, Comparator 2 input pin and an
external capacitor. The pulse is output onto the CTPLS
pin. To enable this mode, set the TGEN bit.
See Figure 27-4 for an example circuit. C
chosen by the user to determine the output pulse width
on CTPLS. The pulse width is calculated by
T = (C
source measurement step (Section 27.3.1 “Current
Source Calibration”) and V is the internal reference
voltage (CV
FIGURE 27-4:
27.7
27.7.1
When the device enters any Sleep mode, the CTMU
module current source is always disabled. If the CTMU
is performing an operation that depends on the current
source when Sleep mode is invoked, the operation may
not
measurements may return erroneous values.
27.7.2
The behavior of the CTMU in Idle mode is determined
by the CTMUSIDL bit (CTMUCONH<5>). If CTMUSIDL
is cleared, the module will continue to operate in Idle
mode. If CTMUSIDL is set, the module’s current source
is disabled when the device enters Idle mode. In this
DS39964B-page 436
terminate
PULSE
Creating a Delay with the CTMU
Module
Operation During Sleep/Idle
Modes
/I)*V, where I is known from the current
REF
SLEEP MODE AND DEEP SLEEP
MODES
IDLE MODE
).
correctly.
TYPICAL CONNECTIONS AND INTERNAL CONFIGURATION FOR PULSE
DELAY GENERATION
C
CTED1
C2INB
PULSE
Capacitance
and
PULSE
EDG1
time
Preliminary
CV
is
Current Source
REF
Comparator
PIC18F47J53
CTMU
C2
An example use of this feature is for interfacing with
variable capacitive-based sensors, such as a humidity
sensor. As the humidity varies, the pulse width output
on CTPLS will vary. The CTPLS output pin can be
connected to an input capture pin and the varying pulse
width is measured to determine the humidity in the
application.
Follow these steps to use this feature:
1.
2.
3.
4.
5.
case, if the module is performing an operation when
Idle mode is invoked, the results will be similar to those
with Sleep mode.
27.8
Upon Reset, all registers of the CTMU are cleared. This
leaves the CTMU module disabled; its current source is
turned off and all configuration options return to their
default settings. The module needs to be re-initialized
following any Reset.
If the CTMU is in the process of taking a measurement at
the time of Reset, the measurement will be lost. A partial
charge may exist on the circuit that was being measured,
and should be properly discharged before the CTMU
makes subsequent attempts to make a measurement.
The circuit is discharged by setting and then clearing the
IDISSEN bit (CTMUCONH<1>) while the A/D Converter
is connected to the appropriate channel.
Set the CPOL bit (CMxCON<5>).
Initialize the comparator voltage reference.
Initialize the CTMU and enable time delay
generation by setting the TGEN bit.
Set EDG1STAT.
When C
reference trip point, an output pulse is generated
on CTPLS.
Effects of a Reset on CTMU
PULSE
charges to the value of the voltage
CTPLS
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