#include <P16F1823.inc>

__CONFIG _CONFIG1, (_FOSC_INTOSC & _WDTE_ON & _PWRTE_ON & _MCLRE_ON & _CP_OFF & _CPD_OFF & _BOREN_OFF & _CLKOUTEN_OFF & _IESO_OFF & _FCMEN_OFF) ;18uA
__CONFIG _CONFIG2, (_WRT_OFF & _PLLEN_OFF & _STVREN_OFF & _BORV_19 & _LVP_ON)

#define OSCCON__16MHz b'01111000'
#define OSCCON___8MHz b'01110000'
#define OSCCON___4MHz b'01101000'
#define OSCCON___2MHz b'01100000'
#define OSCCON___1MHz b'01011000'
#define OSCCON_500KHz b'00111000' ;OSCCON default
#define OSCCON_250KHz b'00110000'
#define OSCCON_125KHz b'00101000'
#define OSCCON__64KHz b'00100000'
#define OSCCON__32KHz b'00011000'
.
.
.
BANKSEL OSCCON ; Switch internal clock speed ...
movlw OSCCON___4MHz ; From settings above
movwf OSCCON

This is with the PLL disabled