I don't think this will help you with your problem but normally you don't touch the DEBUG bit. That is done automatically by the=20 debugging/programming tool when it is needed. At least this is true for later versions (MPLAB X) of the IDE and programming/ debugging tools. /Ruben > A simple program like this does not work in debug mode using internal clo= ck > at 8mhz.. >=20 > // PIC16F88 (supplied at 5v) with ICD2 usb, Mplab 8.92 & C compiler HiTec= h > PICC 9.83 > // Hitech PIC16F88.H used for CONFIG FUSES..=20 > // Simple blinking led test on RB2 pin using internal clock at 8mhz.. > =20 > #include >=20 >=20 > #include "delay.c" //make sure that PIC_CLK in this file is correctly > defined >=20 > __CONFIG( FOSC_INTOSCIO & DEBUG_ON & LVP_OFF & WDTE_OFF & PWRTE_OFF & > BOREN_OFF & CP_OFF & MCLRE_ON );=20 >=20 >=20 > void main(void) > { > int a; >=20 > OSCCON =3D 0b01111000; // Internal oscillator 8mhz=20 > =20 > TRISB =3D 0x00; // PORTB all output =20 > PORTB =3D 0x00; >=20 > while(1) // Blink RB2 > { > PORTB =3D 0x04; > DelayBigMs(500); > PORTB =3D 0x00; > DelayBigMs(500); =20 > } >=20 > } >=20 >=20 >=20 > -- > View this message in context: http://microcontrollers.2385.n7.nabble.com/= PIC16F88-debugging-using-internal-oscillator-issue-tp198964p198979.html > Sent from the MicroControllers - PIC mailing list archive at Nabble.com. > --=20 > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist >=20 >=20 > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2016.0.7294 / Virus Database: 4489/11228 - Release Date: 12/21/1= 5 >=20 --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .