PIC16F876-20/SO Microchip Technology, PIC16F876-20/SO Datasheet - Page 47

• Manufacturer Part Number: PIC16F876-20/SO
• Description: IC MCU FLASH 8KX14 EE 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F876-20/SO

• Program Memory Type: FLASH
• Program Memory Size: 14KB (8K x 14)
• Package / Case: 28-SOIC (7.5mm Width)
• 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: 22
• 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
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 368 B
• Interface Type: MSSP, PSP, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 70 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: 0 C
• On-chip Adc: 10 bit, 5 Channel
• Package: 28SOIC W
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 20 MHz
• Data Rom Size: 256 B
• A/d Bit Size: 10 bit
• A/d Channels Available: 5
• Height: 2.31 mm
• Length: 17.87 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4 V
• Width: 7.49 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT28SO-1 - SOCKET TRANSITION 28SOIC 300MIL309-1073 - ADAPTER 28-SOIC TO 28-SOIC309-1024 - ADAPTER 28-SOIC TO 28-DIP309-1023 - ADAPTER 28-SOIC TO 28-DIP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

At the completion of the write cycle, the WR bit is
cleared and the EEIF interrupt flag bit is set. (EEIF
must be cleared by firmware.) Since the microcontroller
does not execute instructions during the write cycle, the
firmware does not necessarily have to check either
EEIF, or WR, to determine if the write had finished.
EXAMPLE 4-4:
4.6
The PIC16F87X devices do not automatically verify the
value written during a write operation. Depending on
the application, good programming practice may dic-
tate that the value written to memory be verified against
the original value. This should be used in applications
where excessive writes can stress bits near the speci-
fied endurance limits.
BSF
BCF
MOVF
MOVWF
MOVF
MOVWF
MOVF
MOVWF
MOVF
MOVWF
BSF
BSF
BSF
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
NOP
BSF
BCF
2001 Microchip Technology Inc.
EECON1, EEPGD ;Point to Program memory
Write Verify
STATUS, RP1
STATUS, RP0
ADDRL, W
EEADR
ADDRH, W
EEADRH
VALUEL, W
EEDATA
VALUEH, W
EEDATH
STATUS, RP0
EECON1, WREN
INTCON, GIE
0x55
EECON2
0xAA
EECON2
EECON1, WR
INTCON, GIE
EECON1, WREN
FLASH PROGRAM WRITE
;Only disable interrupts
;Two NOPs to allow micro
;
;Bank 2
;Write address
;of desired
;program memory
;location
;Write value to
;program at
;desired memory
;location
;Bank 3
;Enable writes
;if already enabled,
;otherwise discard
;Write 55h to
;EECON2
;Write AAh to
;EECON2
;Start write operation
;to setup for write
;Only enable interrupts
;if using interrupts,
;otherwise discard
;Disable writes
4.7
There are conditions when the device may not want to
write to the EEPROM data memory or FLASH program
memory. To protect against these spurious write condi-
tions, various mechanisms have been built into the
PIC16F87X devices. On power-up, the WREN bit is
cleared and the Power-up Timer (if enabled) prevents
writes.
The write initiate sequence, and the WREN bit
together, help prevent any accidental writes during
brown-out, power glitches, or firmware malfunction.
4.8
The PIC16F87X devices have two code protect mecha-
nisms, one bit for EEPROM data memory and two bits for
FLASH program memory. Data can be read and written
to the EEPROM data memory, regardless of the state of
the code protection bit, CPD. When code protection is
enabled and CPD cleared, external access via ICSP is
disabled, regardless of the state of the program memory
code protect bits. This prevents the contents of EEPROM
data memory from being read out of the device.
The state of the program memory code protect bits,
CP0 and CP1, do not affect the execution of instruc-
tions out of program memory. The PIC16F87X devices
can always read the values in program memory,
regardless of the state of the code protect bits. How-
ever, the state of the code protect bits and the WRT bit
will have different effects on writing to program mem-
ory. Table 4-1 shows the effect of the code protect bits
and the WRT bit on program memory.
Once code protection has been enabled for either
EEPROM data memory or FLASH program memory,
only a full erase of the entire device will disable code
protection.
Protection Against Spurious
Writes
Operation While Code Protected
PIC16F87X
DS30292C-page 45