PIC16F877A-I/P Microchip Technology, PIC16F877A-I/P Datasheet - Page 15

• Manufacturer Part Number: PIC16F877A-I/P
• Description: IC MCU FLASH 8KX14 EE 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F877A-I/P

• Program Memory Type: FLASH
• Program Memory Size: 14KB (8K x 14)
• Package / Case: 40-DIP (0.600", 15.24mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Eeprom Size: 256 x 8
• Ram Size: 368 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 368 B
• Interface Type: CCP/I2C/MSSP/SPI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 33
• Number Of Timers: 3
• 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, DM163022, DV164120
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 444-1001 - DEMO BOARD FOR PICMICRO MCU
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: PIC16F877AI/P

5.0
Checksum is calculated by reading the contents of the
PIC16F87XA memory locations and adding up the
opcodes up to the maximum user addressable location,
e.g., 0x1FF for the PIC16F87XA. Any carry bits
exceeding 16-bits are neglected. Finally, the configura-
tion word (appropriately masked) is added to the
checksum. Checksum computation for each member of
the PIC16F87XA devices is shown in Table 5-1.
The checksum is calculated by summing the following:
• The contents of all program memory locations
• The configuration word, appropriately masked
• Masked ID locations (when applicable)
TABLE 5-1:
 2010 Microchip Technology Inc.
PIC16F873A
PIC16F874A
PIC16F876A
PIC16F877A
Legend: CFGW
Device
SUM[a:b]
SUM_ID
*Checksum =
+
&
CHECKSUM COMPUTATION
CHECKSUM COMPUTATION
=
=
=
=
=
Protect
Code
OFF
OFF
OFF
OFF
ON
ON
ON
ON
Configuration Word
[Sum of locations a to b inclusive]
ID locations masked by 0Fh then made into a 16-bit value with ID0 as the most significant nibble.
For example, ID0 = 01h, ID1 = 02h, ID3 = 03h, ID4 = 04h, then SUM_ID = 1234h
[Sum of all the individual expressions] MODULO [FFFFh]
Addition
Bitwise AND
SUM[0000:0FFF] + (CFGW & 2FCF)
(CFGW & 2FCF) + SUM_ID
SUM[0000:0FFF] + (CFGW & 2FCF)
(CFGW & 2FCF) + SUM_ID
SUM[0000:1FFF] + (CFGW & 2FCF)
(CFGW & 2FCF) + SUM_ID
SUM[0000:1FFF] + (CFGW & 2FCF)
(CFGW & 2FCF) + SUM_ID
Advance Information
Checksum*
The Least Significant 16 bits of this sum are the
checksum.
The following table describes how to calculate the
checksum for each device. Note that the checksum cal-
culation differs depending on the code-protect setting.
Since the program memory locations read out differ-
ently depending on the code-protect setting, the table
describes how to manipulate the actual program mem-
ory values to simulate the values that would be read
from a protected device. When calculating a checksum
by reading a device, the entire program memory can
simply be read and summed. The configuration word
and ID locations can always be read.
Note that some older devices have an additional value
added in the checksum. This is to maintain compatibility
with older device programmer checksums.
PIC16F87XA
Blank
Value
1FCF
1FCF
0FCF
0FCF
4F9E
4F9E
1F9E
1F9E
DS39589C-page 15
25E6h at 0
and max
address
EB9D
EB9D
DB9D
EB6C
DB9D
EB6C
1B6C
1B6C