PIC16F688-I/P Microchip Technology, PIC16F688-I/P Datasheet - Page 65

• Manufacturer Part Number: PIC16F688-I/P
• Description: IC PIC MCU FLASH 4KX14 14DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F688-I/P

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 14-DIP (0.300", 7.62mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 12
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: SCI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 12
• Number Of Timers: 2
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014, DM164120-4
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Data Rom Size: 256 B
• Height: 3.3 mm
• Length: 19.05 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2 V
• Width: 6.35 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC162066 - HEADER INTRFC MPLAB ICD2 20PINAC162061 - HEADER INTRFC MPLAB ICD2 20PINDM163029 - BOARD PICDEM FOR MECHATRONICSAC162056 - HEADER INTERFACE ICD2 16F688ACICE0207 - MPLABICE 14P 300 MIL ADAPTERAC124001 - MODULE SKT PROMATEII 8DIP/SOIC
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

8.0
The analog-to-digital converter (A/D) allows conversion
of an analog input signal to a 10-bit binary representa-
tion of that signal. The PIC16F688 has eight analog
inputs, multiplexed into one sample and hold circuit.
FIGURE 8-1:
8.1
There are three registers available to control the
functionality of the A/D module:
1.
2.
3.
8.1.1
The ANS<7:0> bits (ANSEL<7:0>) and the TRIS bits
control the operation of the A/D port pins. Set the
corresponding TRIS bits to set the pin output driver to
its
corresponding ANSEL bit to disable the digital input
buffer.
8.1.2
There are eight analog channels on the PIC16F688,
AN0
(ADCON0<4:2>) control which channel is connected to
the sample and hold circuit.
 2004 Microchip Technology Inc.
Note:
ANSEL (Register 8-1)
ADCON0 (Register 8-2)
ADCON1 (Register 8-3)
high-impedance
through
ANALOG-TO-DIGITAL
CONVERTER (A/D) MODULE
A/D Configuration and Operation
ANALOG PORT PINS
Analog voltages on any pin that is defined
as a digital input may cause the input
buffer to conduct excess current.
CHANNEL SELECTION
RA1/AN1/V
AN7.
A/D BLOCK DIAGRAM
RC0/AN4
RC1/AN5
RC2/AN6
RC3/AN7
RA0/AN0
RA2/AN2
RA4/AN3
state.
REF
The
Likewise,
CHS<2:0>
CHS<2:0>
V
REF
set
Preliminary
bits
V
the
DD
GO/DONE
VCFG = 0
VCFG = 1
ADON
The output of the sample and hold is connected to the
input of the converter. The converter generates a
binary result via successive approximation and stores
the result in a 10-bit register. The voltage reference
used in the conversion is software selectable to either
V
shows the block diagram of the A/D on the PIC16F688.
8.1.3
There are two options for the voltage reference to the
A/D converter: either V
applied to V
controls the voltage reference selection. If VCFG is set,
then the voltage on the V
otherwise, V
V
DD
SS
or a voltage applied by the V
A/D
ADFM
VOLTAGE REFERENCE
REF
DD
is the reference.
is used. The VCFG bit (ADCON0<6>)
ADRESH ADRESL
DD
is used, or an analog voltage
PIC16F688
10
10
REF
pin is the reference;
REF
DS41203B-page 63
pin. Figure 8-1