PIC16F876A-I/SS Microchip Technology, PIC16F876A-I/SS Datasheet - Page 455

• Manufacturer Part Number: PIC16F876A-I/SS
• Description: IC MCU FLASH 8KX14 EE 28SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F876A-I/SS

• 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-SSOP
• 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
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 368 B
• Interface Type: I2C, SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 1 x 16 bit
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163022, DV164120
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5 bit
• Data Rom Size: 256 B
• Height: 1.75 mm
• Length: 10.2 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4 V
• Width: 5.3 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164307 - MODULE SKT FOR PM3 28SSOPAC164020 - MODULE SKT PROMATEII 44TQFPXLT28SS-1 - SOCKET TRANSITION ICE 28SSOP
• Lead Free Status / Rohs Status: Details
• Other names: PIC16F876AI/SS

24.5
24.5.1
24.5.2
24.5.3
24.5.3.1
24.5.3.2
1997 Microchip Technology Inc.
Using Calibration Data
Parameter Variation
Device Programming
Non-Windowed Parts
Windowed Parts
Calibration Parameters
The Slope A/D module has several analog components. Like all CMOS circuitry the parametric
values vary with process, temperature, voltage, and time. Devices have been designed to mini-
mize the effect of these variations. In addition, each device, with the slope A/D module, is cali-
brated at factory test by measuring several key parameters and storing these values into EPROM
at specified locations. The customer’s application program may access this data and use it to
mathematically compensate for device variations.
Collectively, these data values are referred to as calibration constants. The calibration constants
are listed in
bytes of mantissa. For information on floating point algorithms, refer to AN575.
Table 24-3: Calibration Constants
For additional information on using the calibration parameters see Application Note 624.
The calibration constants should be used by the application firmware to obtain the best accuracy.
K
Table 24-4
used as well as the “Expected Parameter Variation with Calibration.”
If the accuracies without calibration are adequate for the task at hand, no further calibrations of
the module are necessary. If greater accuracy is needed, the calibration constants must be used.
Table 24-4: Parameter Variation
Non-windowed parts are programmed just like any PIC16CXXX processor. The calibration area
is write-protected during factory calibration.
Calibration data must be read out and saved before erasing a windowed part. There is no way to
recreate these values, so if they are lost the part can no longer be calibrated.
A/D Slope reference ratio
Bandgap reference voltage
K
K
Symbol
REF
Caution:
Windowed parts must not be write-protected. If the parts are erased by ultraviolet light, the
calibration parameters are lost and cannot be reprogrammed once the part has been
write-protected.
REF
BG
and K
A/D slope reference ratio
Bandgap reference voltage
lists the “Maximum Parameter Variation” attainable when the calibration data is not
BG
Table
Parameter
are used in A/D conversions.
24-3. The 32-bit floating point representation has an exponent byte, and three
Parameter
Section 24. Slope A/D
Symbol
K
K
REF
BG
+/- 2.2%
+/- 4.2%
Without Calibration
Maximum Variation
Number of
Bytes
4
4
+/- 0.13%
+/- 0.058%
Achievable Variation
32-bit Floating Point
32-bit Floating Point
Representation of
with Calibration
DS31024A-page 24-13
Value
24