PIC16F721-I/ML Microchip Technology, PIC16F721-I/ML Datasheet - Page 26

• Manufacturer Part Number: PIC16F721-I/ML
• Description: MCU PIC 4K FLASH 20-QFN
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 16Fr

Specifications of PIC16F721-I/ML

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Core Processor: PIC
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Number Of I /o: 17
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 12x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-VFQFN Exposed Pad
• Controller Family/series: PIC16F
• No. Of I/o's: 18
• Ram Memory Size: 256Byte
• Cpu Speed: 16MHz
• No. Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PIC16(L)F720/721
7.3.2
With the program code protection enabled, the
checksum is computed in the following manner: the
Least Significant nibble of each user ID is used to
create a 16-bit value. The masked value of user ID
location 2000h is the Most Significant nibble. This Sum
of user IDs is summed with the Configuration Words (all
unimplemented Configuration bits are masked to ’0’).
Example 7-5
a blank device and for a device with 00AAh at the first
and last program memory locations. Also, see
for Configuration Word mask values with code protection
enabled.
EXAMPLE 7-5:
DS41409B-page 26
Note 1: User ID values in this example are random values.
PIC16F720 Configuration Word 1
2: Configuration Word 1 and 2 = all bits are ‘1’, except the code-protect enable bit.
3: Configuration Word 1 and 2 Mask = all Configuration Word bits are set to ‘1’, except for unimplemented
4: << = shift left, thus the LSb of the first user ID value is the MSb of the sum of user IDs and so on until
CODE PROTECTION ENABLED
through
bits which read ‘0’.
the LSb of the last user ID value becomes the LSb of the sum of user IDs.
Configuration Word 1 mask
Configuration Word 2
Configuration Word 2 mask
User ID (2000h)
User ID (2001h)
User ID (2002h)
User ID (2003h)
Sum of User IDs
Checksum
Example 7-8
CHECKSUM COMPUTED WITH CODE PROTECTION ENABLED (PIC16F720),
BLANK DEVICE
shown below are for
(1)
(1)
(1)
(1)
(4)
= (3FBFh and 337Bh) + (3FFFh and 0013h) + Sum of User IDs
= 4AFDh
= 1000h + 0700h + 00A0h + 000Fh
= 17AFh
= 333Bh +0013h + 17AFh
(2)
(2)
= (0001h and 000Fh) << 12 + (0007h and 000Fh) << 8 +
(000Ah and 000Fh) << 4 + (000Fh and 000Fh)
Advance Information
Table 7-1
(3)
(3)
0001h
0007h
000Ah
000Fh
3FBFh
337Bh
3FFFh
0013h
 2011 Microchip Technology Inc.