PIC16F877-20/P Microchip Technology, PIC16F877-20/P Datasheet - Page 110

• Manufacturer Part Number: PIC16F877-20/P
• Description: IC MCU FLASH 8KX14 EE 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F877-20/P

• Core Size: 8-Bit
• Program Memory Size: 14KB (8K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 368 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Controller Family/series: PIC16F
• No. Of I/o's: 33
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 368Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 444-1001 - DEMO BOARD FOR PICMICRO MCU
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

PICmicro MID-RANGE MCU FAMILY
6.5
DS31006A-page 6-16
Design Tips
Question 1:
Answer 1:
When a device with more then 2K words of program memory is used, the calling of subroutines
may require that the PCLATH register be loaded prior to the CALL (or GOTO) instruction to specify
the correct program memory page that the routine is located on. The following instructions will
correctly load PCLATH register, regardless of the program memory location of the label SUB_1.
SUB_1
Question 2:
Answer 2:
Example 6-4
of the code may be removed.
MOVLW
MOVWF
CALL
:
:
:
:
RETURN
shows this. If the device you are using does not use all 4 data memory banks, some
Program execution seems to get lost.
I need to initialize RAM to ’0’s. What is an easy way to do that?
HIGH (SUB_1)
PCLATH
SUB_1
; Select Program Memory Page of
;
; Call the desired routine
; Start of routine
; Return from routine
Routine.
1997 Microchip Technology Inc.