PIC16F873A-I/SS Microchip Technology, PIC16F873A-I/SS Datasheet - Page 15

• Manufacturer Part Number: PIC16F873A-I/SS
• Description: IC MCU FLASH 4KX14 EE 28SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F873A-I/SS

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K 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: 128 x 8
• Ram Size: 192 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: 128Byte
• Ram Memory Size: 192Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Core: PIC
• Processor Series: PIC16F
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 20 MHz
• Data Ram Size: 192 B
• Data Rom Size: 128 B
• On-chip Adc: Yes
• Number Of Programmable I/os: 22
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 5
• Height: 1.75 mm
• Interface Type: I2C, SPI, USART
• Length: 10.2 mm
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• 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: PIC16F873AI/SS

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