PIC16F74-I/P Microchip Technology, PIC16F74-I/P Datasheet - Page 516

• Manufacturer Part Number: PIC16F74-I/P
• Description: IC MCU FLASH 4KX14 A/D 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F74-I/P

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Number Of I /o: 33
• Program Memory Type: FLASH
• Ram Size: 192 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Controller Family/series: PIC16F
• No. Of I/o's: 33
• Ram Memory Size: 192Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Package: 40PDIP
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 20 MHz
• Operating Supply Voltage: 5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 33
• Interface Type: I2C/SPI/USART
• On-chip Adc: 8-chx8-bit
• Number Of Timers: 3
• Processor Series: PIC16F
• Core: PIC
• Data Ram Size: 192 B
• Maximum Clock Frequency: 20 MHz
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: ICE2000, DM163022
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 444-1001 - DEMO BOARD FOR PICMICRO MCU
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

PICmicro MID-RANGE MCU FAMILY
28.7
DS31028A-page 28-8
Field Programming of PICmicro OTP MCUs
An OTP device is not normally capable of being reprogrammed, but the PICmicro architecture
gives you this flexibility provided the size of your firmware is at least half that of the desired device
and the device is not code protected. If your target device does not have enough program mem-
ory, Microchip provides a wide spectrum of devices from 0.5K to 8K program memory with the
same set of peripheral features that will help meet the criteria.
The PIC16CXXX microcontrollers have two vectors, reset and interrupt, at locations 0x0000 and
0x0004. When the PICmicro encounters a reset or interrupt condition, the code located at one of
these two locations in program memory is executed. The first listing of
code that is first programmed into the PICmicro. The second listing of
code that is programmed into the PICmicro for the second time.
Example 28-2
originally goto Main (0x2808), is reprogrammed to all 0’s which happens to be a NOP instruction.
This location cannot be reprogrammed to the new opcode (0x2860) because the bits that are 0’s
cannot be reprogrammed to 1’s, only bits that are 1’s can be reprogrammed to 0’s. The next mem-
ory location 0x0001 was originally blank (all 1’s) and now becomes a goto Main (0x2860). When
a reset condition occurs, the PICmicro executes the instruction at location 0x0000 which is the
NOP , a completely benign instruction, and then executes the goto Main to start the execution of
code. The example also shows that all program memory locations after 0x005A are blank in the
original program so that the second time the PICmicro is programmed, the revised code can be
programmed at these locations. The same descriptions can be given for the interrupt vector at
location 0x0004.
This method changes slightly for PICmicros with >2K words of program memory. Each of the
goto
Example 28-1
Example 28-1:
Now your one-time programmable PICmicro is exhibiting EEPROM- or Flash-like qualities.
movlw <page>
movwf PCLATH
goto
Main and goto
Main
shows that to program the PICmicro a second time the memory location 0x0000,
due to paging on devices with >2K words of program memory.
Crossing Program Memory Pages
ISR instructions are replaced by the following code segment is
movlw <page>
movwf PCLATH
goto
ISR
1997 Microchip Technology Inc.
Example 28-2
Example 28-2
shows the
shows the