;********************************************************************** ; * ; Filename: crctest.asm * ; Date: 18 Jul 2002 * ; File Version: 1 * ; * ; Author: Chris White (whitecf@bcs.org.uk) * ; Company: Monitor Computing Services Ltd. * ; * ;********************************************************************** ; * ; Copyright (C) 2002 Monitor Computing Services Ltd. * ; * ; This program is free software; you can redistribute it and/or * ; modify it under the terms of the GNU General Public License * ; as published by the Free Software Foundation; either version 2 * ; of the License, or any later version. * ; * ; This program is distributed in the hope that it will be useful, * ; but WITHOUT ANY WARRANTY; without even the implied warranty of * ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * ; GNU General Public License for more details. * ; * ; You should have received a copy of the GNU General Public * ; License (http://www.gnu.org/copyleft/gpl.html) along with this * ; program; if not, write to: * ; The Free Software Foundation Inc., * ; 59 Temple Place - Suite 330, * ; Boston, MA 02111-1307, * ; USA. * ; * ;********************************************************************** ; * ; Notes: 'Main' program to test CRC16 algorithm implementations. * ; * ;********************************************************************** list p=16C84 #include __CONFIG _CP_OFF & _WDT_OFF & _PWRTE_ON & _XT_OSC ; '__CONFIG' directive is used to embed configuration data within .asm file. ; The lables following the directive are located in the respective .inc file. ; See respective data sheet for additional information on configuration word. ;********************************************************************** ; Include and configuration directives * ;********************************************************************** #include ;********************************************************************** ; Constant definitions * ;********************************************************************** ;********************************************************************** ; Variable definitions * ;********************************************************************** CBLOCK 0x0C ; Status and accumulator storage registers w_isr ; 'w' register, accumulator, store during ISR pclath_isr ; PCLATH register store during ISR status_isr ; status register store during ISR ; Test data byte testByte ; HDLC CRC values hdlcCrc1H hdlcCrc1L hdlcCrc2H hdlcCrc2L ENDC ;********************************************************************** ; Reset vector * ;********************************************************************** ORG 0x000 ; Processor reset vector BootVector clrf INTCON ; Disable interrupts clrf INTCON ; Ensure interrupts are disabled goto Main ; Jump to beginning of program ;********************************************************************** ; Interrupt vector * ;********************************************************************** ORG 0x004 ; Interrupt vector location IntVector movwf w_isr ; Save off current W register contents swapf STATUS,W ; Move status register into W register BANKSEL TMR0 ; Ensure register page 0 is selected movwf status_isr ; save off contents of STATUS register movf PCLATH,W ; Move PCLATH register into W register movwf pclath_isr ; save off contents of PCLATH register movlw high BeginISR ; Load ISR address high byte ... movwf PCLATH ; ... into PCLATH to set code block goto BeginISR ; Jump to interrupt service routine ;********************************************************************** ; Interrupt service routine (ISR) code * ;********************************************************************** BeginISR btfss INTCON,T0IF ; Skip if RTCC interrupt flag is set ... goto EndISR ; ... otherwise jump to end of service routine BANKSEL TMR0 ; Ensure register page 0 is selected #ifdef CLKPORT bcf CLKPORT,CLKBIT ; Set clock output low #endif bcf INTCON,T0IF ; Clear the RTCC interrupt bitflag #ifdef CLKPORT bsf CLKPORT,CLKBIT ; Set clock output high #endif EndISR movf pclath_isr,W ; Retrieve copy of PCLATH register movwf PCLATH ; Restore pre-isr PCLATH register contents movf status_isr,W ; Retrieve copy of STATUS register movwf STATUS ; Restore pre-isr STATUS register contents swapf w_isr,F swapf w_isr,W ; Restore pre-isr W register contents retfie ; Return from interrupt ;********************************************************************** ; Main program code * ;********************************************************************** CRCHDLC macro testData, hdlcCrcL, hdlcCrcH movlw testData movwf testByte CrcHDLC testByte, hdlcCrcL, hdlcCrcH endm Main clrf PORTA ; Clear I/O ports clrf PORTB ; Test HDLC CRC clrf hdlcCrc1H decf hdlcCrc1H,F clrf hdlcCrc1L decf hdlcCrc1L,F CRCHDLC '0', hdlcCrc1L, hdlcCrc1H CRCHDLC '1', hdlcCrc1L, hdlcCrc1H CRCHDLC '2', hdlcCrc1L, hdlcCrc1H CRCHDLC '3', hdlcCrc1L, hdlcCrc1H CRCHDLC '4', hdlcCrc1L, hdlcCrc1H CRCHDLC '5', hdlcCrc1L, hdlcCrc1H CRCHDLC '6', hdlcCrc1L, hdlcCrc1H CRCHDLC '7', hdlcCrc1L, hdlcCrc1H CRCHDLC '8', hdlcCrc1L, hdlcCrc1H CRCHDLC '9', hdlcCrc1L, hdlcCrc1H CRCHDLC 'A', hdlcCrc1L, hdlcCrc1H CRCHDLC 'B', hdlcCrc1L, hdlcCrc1H CRCHDLC 'C', hdlcCrc1L, hdlcCrc1H CRCHDLC 'D', hdlcCrc1L, hdlcCrc1H CRCHDLC 'E', hdlcCrc1L, hdlcCrc1H CRCHDLC 'F', hdlcCrc1L, hdlcCrc1H clrf hdlcCrc2H decf hdlcCrc2H,F clrf hdlcCrc2L decf hdlcCrc2L,F CRCHDLC 'H', hdlcCrc2L, hdlcCrc2H CRCHDLC 'e', hdlcCrc2L, hdlcCrc2H CRCHDLC 'l', hdlcCrc2L, hdlcCrc2H CRCHDLC 'l', hdlcCrc2L, hdlcCrc2H CRCHDLC 'o', hdlcCrc2L, hdlcCrc2H sleep end ; directive 'end of program'