PIC16F876AT-I/SO Microchip Technology, PIC16F876AT-I/SO Datasheet - Page 454

• Manufacturer Part Number: PIC16F876AT-I/SO
• Description: IC MCU CMOS 20MHZ 8K FLSH 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F876AT-I/SO

• Core Size: 8-Bit
• Program Memory Size: 14KB (8K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 368 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SOIC (7.5mm Width)
• Controller Family/series: PIC16F
• No. Of I/o's: 22
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 368Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PICmicro MID-RANGE MCU FAMILY
24.4
24.4.1
24.4.2
DS31024A-page 24-12
REFOFF (SLPCON<5>)
Bandgap Voltage Reference
Slope Reference Voltage Divider
SREFLO
K
Other Analog Modules
REF
Reference
Bandgap
=
~
Additional analog modules for mixed signal applications are required. These include:
• bandgap voltage reference
• slope reference voltage divider
The bandgap reference circuit is used to generate a 1.2V nominal stable voltage reference for
the Slope A/D, the low-voltage detector, and the slope reference divider. The bandgap reference
voltage is available on the analog MUX. To enable the bandgap reference REFOFF (SLP-
CON<5>) must be cleared. The bandgap reference must be enabled for any slope A/D conver-
sion.
The bandgap reference calibration factor is stored in the calibration space EPROM.
The slope reference voltage divider circuit, consisting of a buffer amplifier and resistor divider, is
connected to the internal bandgap reference producing two other voltage references called
SREFHI and SREFLO (see
1.2V, and SREFLO is nominally 0.13V. These reference voltages are available on two of the ana-
log multiplexer channels. The Slope A/D module and firmware can measure the SREFHI and
SREFLO voltages, and in conjunction with the K
ADC's offset and slope errors.
See AN624 for further details.
Figure 24-3: Slope Reference Divider
SREFHI
SREFHI - SREFLO
9
SREFLO
V
REF
ADOFF (SLPCON<0>)
Figure
+
_
24-3). SREFHI is nominally the same as the bandgap voltage,
REF
and K
BG
calibration data correct for the
1997 Microchip Technology Inc.
SREFHI
SREFLO
To Slope A/D
MUX