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Migration from 16F877A to 16F887

The PIC16F877A is an older part that is becoming obsolete. In our bundled development systems, we have replaced the 16F877A with the more modern 16F887. However, many of the books that we sell only have sample programs for the 16F877A. This is especially problematic in the book "LAB-X1 Tutorial and Resource Book" by Harprit Sandhu, which is included in our Super Bundle development system. The following information is intended to assist in converting programs for use with the 16F887. The syntax below is for PICBASIC PRO Compiler.

Much of the function of the 16F877A ADCON1 register has been moved to the ANSEL and ANSELH registers in the 16F887:

ADCON1 (16F877A)	ANSEL (16F887)	ANSELH (16F887)	ADCON1 (16F887)	DESCRIPTION
ADCON1 = %00000000 '($00, 0)	ANSEL = %00011111	ANSELH = %00000000		PORTA analog
ADCON1 = %00000100 '($04, 4)	ANSEL = %00001011	ANSELH = %00000000		AN0, AN1, AN3 analog
ADCON1 = %00000110 '($06, 6)	ANSEL = %00000000	ANSELH = %00000000		All pins digital
ADCON1 = %00000111 '($07, 7)	ANSEL = %00000000	ANSELH = %00000000		All pins digital
ADCON1 = %00001110 '($0E, 14)	ANSEL = %00000001	ANSELH = %00000000		AN0 analog
ADCON1 = %10000010 '($82, 130)	ANSEL = %00011111	ANSELH = %00000000	ADCON1.7 = 1	PORTA analog, result right-justified
ADCON1.7 = 1			ADCON1.7 = 1	result right-justified

DEFINE ADC_CLOCK does not function on the 16F887. This define must be replaced by a setting to the ADCON0 register:

DEFINE for16F877A	ADCON0 setting for 16F887
DEFINE ADC_CLOCK 0	ADCON0 = %00000000
DEFINE ADC_CLOCK 1	ADCON0 = %01000000
DEFINE ADC_CLOCK 2	ADCON0 = %10000000
DEFINE ADC_CLOCK 3	ADCON0 = %11000000

PIC, PICmicro, dsPIC, and MPLAB are registered trademarks of Microchip Technology Inc. in the USA and other countries. PICBASIC, PICBASIC PRO, PICPROTO, and EPIC are trademarks of Microchip Technology Inc. in the USA and other countries. BASIC Stamp is a trademark of Parallax, Inc.