PIC16F87-I/ML Microchip Technology, PIC16F87-I/ML Datasheet - Page 17

• Manufacturer Part Number: PIC16F87-I/ML
• Description: IC MCU FLASH 4KX14 EEPROM 28QFN
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F87-I/ML

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Oscillator Type: Internal
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 368 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Controller Family/series: PIC16F
• No. Of I/o's: 16
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 368Byte
• Cpu Speed: 20MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT28QFN3 - SOCKET TRAN ICE 18DIP/28QFNAC164322 - MODULE SOCKET MPLAB PM3 28/44QFNAC164033 - ADAPTER 28QFN TO 18DIPDV007003 - PROGRAMMER UNIVERSAL PROMATE II
• Data Converters: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

5.0
6.0
Checksum is calculated by reading the contents of the
PIC16F87/88 memory locations and totaling the
opcodes, up to the maximum user-addressable
location (e.g., 0xFFF for the PIC16F87/88). Any carry
bits exceeding 16 bits are neglected. Finally, the
Configuration Word (appropriately masked) is added to
the checksum. Checksum computation for each
member of the PIC16F87/88 devices is shown in
Table 6-1.
The checksum is calculated by summing the following:
• The contents of all program memory locations
• The Configuration Words, appropriately masked
• Masked ID locations (when applicable)
TABLE 6-1:
 2010 Microchip Technology Inc.
PIC16F87
PIC16F88
Legend: CFGW
To allow portability of code, the programmer is required to read the Configuration Word and ID locations from the HEX
file when loading the HEX file. If Configuration Word information was not present in the HEX file, a simple warning
message may be issued. Similarly, while saving a HEX file, Configuration Word and ID information must be included.
An option to not include this information may be provided.
Specifically for the PIC16F87/88, the EEPROM data memory should also be embedded in the HEX file (see
Section 3.2 “Data EEPROM Memory”).
Microchip Technology Inc. feels strongly that this feature is important for the benefit of the end customer.
Device
EMBEDDING CONFIGURATION WORD AND ID INFORMATION IN HEX FILE
CHECKSUM COMPUTATION
SUM[a:b] = [Sum of locations a to b inclusive]
SUM_ID
*Checksum = [Sum of all the individual expressions] MODULO [0xFFFF]
+
&
Protect
CHECKSUM COMPUTATION
Code-
OFF
OFF
ON
ON
= Configuration Word
= ID locations masked by 0xF, then made into a 16-bit value with ID0 as the Most Significant
= Addition
= Bitwise AND
nibble.
For example, ID0 = 0x1, ID1 = 0x2, ID3 = 0x3, ID4 = 0x4, then SUM_ID = 0x1234.
SUM(0000:0FFF) + (CONFIG0 & 3FFF) + (CONFIG1 & 0003)
(CONFIG0 & 3FFF) + (CONFIG1 & 0003) + SUM_ID
SUM(0000:0FFF) + (CONFIG0 & 3FFF) + (CONFIG1 & 0003)
(CONFIG0 & 3FFF) + (CONFIG1 & 0003) + SUM_ID
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
calculation differs depending on the code protect
setting. Since the program memory locations read out
differently depending on the code protect setting, the
table describes how to manipulate the actual program
memory 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 Words 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.
PIC16F87/88
Blank
Value
3002
5004
3002
5004
DS39607C-page 17
0x25E6 at 0
and Max
Address
FBD0
FBD0
IBD2
IBD2