PIC18F85K22-I/PT Microchip Technology, PIC18F85K22-I/PT Datasheet - Page 351

• Manufacturer Part Number: PIC18F85K22-I/PT
• Description: IC, 8BIT MCU, PIC18F, 64MHZ, TQFP-80
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F85K22-I/PT

• Controller Family/series: PIC18
• No. Of I/o's: 69
• Eeprom Memory Size: 1KB
• Ram Memory Size: 2KB
• Cpu Speed: 64MHz
• No. Of Timers: 8
• Core Size: 8 Bit
• Program Memory Size: 32KB
• Core Processor: PIC
• Speed: 64MHz
• Connectivity: EBI/EMI, I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 24x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TQFP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

23.0
The Analog-to-Digital (A/D) Converter module in the
PIC18F87K22 family of devices has 16 inputs for the
64-pin devices and 24 inputs for the 80-pin devices.
This module allows conversion of an analog input
signal to a corresponding 12-bit digital number.
The module has these registers:
• A/D Control Register 0 (ADCON0)
• A/D Control Register 1 (ADCON1)
• A/D Control Register 2 (ADCON2)
• A/D Port Configuration Register 0 (ANCON0)
• A/D Port Configuration Register 1 (ANCON1)
• A/D Port Configuration Register 2 (ANCON2)
• ADRESH (the upper, A/D Results register)
• ADRESL (the lower, A/D Results register)
The ADCON0 register, shown in
trols the operation of the A/D module. The ADCON1
register, shown in
reference and special trigger selection. The ADCON2
register, shown in
clock source and programmed acquisition time and
justification.
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12-BIT ANALOG-TO-DIGITAL
CONVERTER (A/D) MODULE
Register
Register
23-2, configures the voltage
23-3, configures the A/D
Register
23-1, con-
PIC18F87K22 FAMILY
23.1
The converter in PIC18F87K22 family devices is
implemented as a differential A/D where the differential
voltage between two channels is measured and
converted to digital values (see
The converter can also be configured to measure a
voltage from a single input by clearing the CHSN bits
(ADCON1<2:0>). With this configuration, the negative
channel input is connected internally to AV
Figure
FIGURE 23-1:
Differential conversion feeds the two input channels to
a unity gain differential amplifier. The positive channel
input is selected using the CHS bits (ADCON0<6:2>)
and the negative channel input is selected using the
CHSN bits (ADCON1<2:0>).
The output from the amplifier is fed to the A/D Con-
verter, as shown in
available on the ADRESH and ADRESL registers. An
additional bit indicates if the 12-bit result is a positive or
negative value.
FIGURE 23-2:
In the Single Channel Measurement mode, the nega-
tive input is connected to A
bits (ADCON1<2:0>).
Positive Input
CHS<4:0>
Negative Input
CHSN<2:0>
Positive Input
CHS<4:0>
CHSN<2:0> = 000
23-2).
Differential A/D Converter
Figure
DIFFERENTIAL CHANNEL
MEASUREMENT
SINGLE CHANNEL
MEASUREMENT
VSS
23-1. The 12-bit result is
Figure
by clearing the CHSN
DS39960D-page 351
23-1).
ADC
ADC
SS
(see