PIC16F1937-E/MV Microchip Technology, PIC16F1937-E/MV Datasheet - Page 320

• Manufacturer Part Number: PIC16F1937-E/MV
• Description: 14KB Flash, 512B RAM, 256B EEPROM, LCD, 1.8-5.5V 40 UQFN 5x5x0.5mm TUBE
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 16Fr

Specifications of PIC16F1937-E/MV

• Processor Series: PIC16F
• Core: PIC
• Program Memory Type: Flash
• Program Memory Size: 14 KB
• Data Ram Size: 256 B
• Interface Type: MI2C, SPI, EUSART
• Number Of Timers: 5
• Operating Supply Voltage: 1.8 V to 5.5 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: UQFN-40
• Development Tools By Supplier: MPLAB IDE Software
• Minimum Operating Temperature: - 40 C
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 32MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 36
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 14x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Lead Free Status / Rohs Status: Details

PIC16(L)F1934/6/7
26.1
The CPS module can monitor up to 16 inputs. The
capacitive sensing inputs are defined as CPS<15:0>.
To determine if a frequency change has occurred the
user must:
• Select the appropriate CPS pin by setting the
• Set the corresponding ANSEL bit.
• Set the corresponding TRIS bit.
• Run the software algorithm.
Selection of the CPSx pin while the module is enabled
will cause the capacitive sensing oscillator to be on the
CPSx pin. Failure to set the corresponding ANSEL and
TRIS bits can cause the capacitive sensing oscillator to
stop, leading to false frequency readings.
26.2
The capacitive sensing oscillator consists of a constant
current source and a constant current sink, to produce
a triangle waveform. The CPSOUT bit of the
CPSCON0 register shows the status of the capacitive
sensing oscillator, whether it is a sinking or sourcing
current. The oscillator is designed to drive a capacitive
load (single PCB pad) and at the same time, be a clock
source to either Timer0 or Timer1. The oscillator has
three different current settings as defined by
CPSRNG<1:0> of the CPSCON0 register. The different
current settings for the oscillator serve two purposes:
• Maximize the number of counts in a timer for a
• Maximize the count differential in the timer during
26.3
The capacitive sensing oscillator uses voltage refer-
ences to provide two voltage thresholds for oscillation.
The upper voltage threshold is referred to as Ref+ and
the lower voltage threshold is referred to as Ref-.
The V
(Ref-) and the V
threshold level (Ref+).
DS41364E-page 320
CPSCH<3:0> bits of the CPSCON1 register.
fixed time base.
a change in frequency.
SS
Analog MUX
Capacitive Sensing Oscillator
Voltage References
voltage determines the lower threshold level
DD
voltage determines the upper
26.4
The capacitive sensing oscillator can operate in one of
three different power modes.
There are three distinct power ranges; low, medium and
high. Current consumption is dependent upon the range
selected. See
selection.
The remaining mode is a Noise Detection mode that
resides within the high range. The Noise Detection
mode is unique in that it disables the sinking and sourc-
ing of current on the analog pin but leaves the rest of
the oscillator circuitry active. This reduces the oscilla-
tion frequency on the analog pin to zero and also
greatly reduces the current consumed by the oscillator
module.
When noise is introduced onto the pin, the oscillator is
driven at the frequency determined by the noise. This
produces a detectable signal at the comparator output,
indicating the presence of activity on the pin.
Figure 26-2
current sources and comparators associated with the
oscillator.
TABLE 26-1:
CPSRNG<1:0>
Note 1: See the applicable Electrical Specifica-
00
01
10
11
Power Ranges
tions Chapter for more information.
shows a more detailed drawing of the
Table 26-1
POWER RANGE SELECTION
 2008-2011 Microchip Technology Inc.
Medium
Mode
High
Low
Off
for proper power range
Nominal Current
0.0 A
0.1 A
1.2 A
18 A
(1)