Any success stories with CAN bus on PDS?

[rcurl]

I am just starting a new project in which I will need to control motors, drive solenoids, read switches and pots, monitor voltages, etc. at several locations in a large piece of equipment. The number and type of devices to monitor and control will change with each machine built, so I need this to be very modular.

I am looking at using CAN bus by connecting a MCP2515 CAN controller to a PIC, and then use CAN I/O expanders (MCP250xx) on remote node boards.

Has anyone done anything like this with PDS? I have found a few brief threads in the forum, but there's not a lot of information there.

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CAN is a very powerful industrial and automotive communications bus - but it also appears to be very difficult to implement. Any information or code samples would be GREATLY appreciated!

Thanx!

Rick

[Alan]

Hi

I know you can implement Canbus operation with a Can to spi interface IC. I dont know if you have looked at this kind of chip. As you say Can works in a harsh enviromrnt.

Regards

Alan

[RGV250]

Hi,
I am playing with CAN using 18F458 as these have a CAN module built in so all you need are the transceivers (DIL ones are as rare as rocking horse poo). I am only trying it in loopback mode at the moment so the chip is in itself talking to itself but it all seems to work. I think I am now at the point to build the hardware to see what happens. If you are interested I will tidy up and comment the demo and post it. I am not concerned with the full CAN spec, more for simple messages in a noisy envoirenment.

Bobby

[rcurl]

I'll be using an 18F4620 (which doesn't have CAN capability) driving an MCP2515 CAN controller using the SPI interface. I am trying to talk to a bunch of remote MCP25050 CAN I/O expanders. I bought one of Microchip's MCP250xx CAN development boards, and that is working fine (it has three nodes on it), but I am still not having much luck getting a PIC to talk to it. I got so desperate that I just bought a Mikroelektronika basic compiler just because it has built-in CAN libraries. I've got to work on another project for a couple of weeks before I get back to this one.

I'd love to see any code you've got that works, 'cause I'd sure rather do this using Proton!

By the way, both http://www.digikey.com and http://www.mouser.com have the MCP2515 transceivers in the DIL package in stock.

-Rick

[RGV250]

Rick,
I chose the 18F458 as it has a CAN module built in and hence only requires the transceivers, (which the I/O expander requires as well and an oscillator) you do not have to use the SPI, just read and write to the registers. I did look
at the I/O expanders but could not see the point as you have to configure them up so where I want more I/O I am just using another PIC. The PIC has more I/O already built in, size may be an issue for me but I will probably look at the 258 which still has 25 I/O.
At the moment the code is in Loopback mode so all it does is write to the transmit buffers and then reads the receive buffers and sends it out to a 4 x 20 LCD, I think it works enough to commit to building a demo board which I hope to have built later on in the week.
Hopefully it will help you out.

Regards,
Bobby

'****************************************************************
'*  Name    : RGV_BUS_TEST_2.BAS                                *
'*  Author  : Bobby Garrett                                     *
'*  Notice  : Copyright (c) 2005 Bobby Garrett                  *
'*          : All Rights Reserved                               *
'*  Date    : 19/10/2005                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          :                                                   *
'****************************************************************
                               
        Device = 18F458
        XTAL = 20
        
        'Set up PIC registers
        @CONFIG_REQ
        @__CONFIG config1h, OSCS_OFF_1 & HS_OSC_1
        @__CONFIG config2l, BOR_ON_2 & BORV_42_2 & PWRT_ON_2
        @__CONFIG config2h, WDT_OFF_2
        @__CONFIG config4l, STVR_ON_4 & LVP_OFF_4 & DEBUG_OFF_4
        
        '@CONFIG_REQ
        '@__CONFIG CONFIG1H, OSCS_OFF_1 & HS_OSC_1
        '@__CONFIG CONFIG2L, BOR_ON_2 & BORV_42_2 & PWRT_ON_2
        '@__CONFIG CONFIG2H, WDT_OFF_2 & WDTPS_128_2
        '@__CONFIG CONFIG3H, CCP2MX_ON_3
        '@__CONFIG CONFIG4L, STVR_ON_4 & LVP_OFF_4 & DEBUG_OFF_4
        
        

'Set the CAN I/O pins        
        Declare CAN_Txpin = PORTB.cantx 'Set CAN Transmit pin
        Declare CAN_Rxpin = PORTB.canrx 'Set CAN Receive pin
                      		
        Dim x As Byte   'Loop counter 
        Dim Module1 As Byte
        Dim Module2 As Byte
        Dim Module3 As Byte
        Dim Module4 As Byte
        Dim Module5 As Byte
      
GoTo INIT
 
send: 
        Cls                      'Clear screen  For testing
        For x = 0 To 50          'For testing
        TXB0D0 = x               'For testing
       
        RXB0CON = %00100000      'Receive only valid messages with standard identifier                                
                                       
        CANCON = %01001000       'loopback mode for testing only !!!! 
                                 'Transmit buffer 0
        
        'Every count of 10 change the Tx identifier to simulate different unit
        If x <= 10 Then TXB0SIDL = %00100000 : TXB0SIDH = %00000000
        If x > 10 And x <= 20 Then TXB0SIDL = %01000000 : TXB0SIDH = %00000000
        If x > 20 And x <= 30 Then TXB0SIDL = %01100000 : TXB0SIDH = %00000000
        If x > 30 And x <= 40 Then TXB0SIDL = %10000000 : TXB0SIDH = %00000000
        If x > 40 And x <= 50 Then TXB0SIDL = %10100000 : TXB0SIDH = %00000000
                               
        TXB0CON = %00001001      'Start transmition, priority level 1 
        
WAIT_TX_OK: If TXB0CON.3 = 1 Then WAIT_TX_OK 'Loop until TX succesfull
                                             '(change when working OK)
 
        CANCON = %01000000       'loopback mode For testing only !!!!
        
        'Every count of 10 change the Rx identifier to recieve message from "correct module"
        If x <= 10 Then RXB0SIDL = %00100000 : RXB0SIDH = %00000000 : Module1 = RXB0D0
        If x > 10 And x <= 20 Then RXB0SIDL = %01000000 : RXB0SIDH = %00000000 : Module2 = RXB0D0
        If x > 20 And x <= 30 Then RXB0SIDL = %01100000 : RXB0SIDH = %00000000 : Module3 = RXB0D0
        If x > 30 And x <= 40 Then RXB0SIDL = %10000000 : RXB0SIDH = %00000000 : Module4 = RXB0D0
        If x > 40 And x <= 50 Then RXB0SIDL = %10100000 : RXB0SIDH = %00000000 : Module5 = RXB0D0
     
        DelayMS 500             'For testing
       
        Print At 1,1, Dec x         'For testing
        Print At 2,1, Dec Module1   'For testing
        Print At 2,5, Dec Module2   'For testing
        Print At 2,9, Dec Module3   'For testing
        Print At 2,13, Dec Module4  'For testing
        Print At 2,17, Dec Module5  'For testing
        
        Print At 2,21, Dec TXERRCNT, " TX ERR" 'For testing
        Print At 2,31, Dec RXERRCNT, " RX ERR" 'For testing
      
        Next x                      'For testing
        GoTo send                   'For testing

INIT:
        ALL_DIGITAL = True       'Set all I/O to digital

'Set Diplay up
        Declare LCD_TYPE 0 
        Declare LCD_INTERFACE 4
        Declare LCD_LINES 2
        LCD_DTPIN = PORTD.4
        LCD_ENPIN = PORTD.2
        LCD_RSPIN = PORTD.3        
               
'Set up the CAN module               
        CANCON = %10000000       'Select config mode
        TXB0CON = 0              'Clear transmit buffer 0 control register
        TXB0DLC = %00001000      'RTR bit cleared, 8 byte data length
        RXB0DLC = %00001000      '8 byte data length
        
'Set up the CAN module acceptance masks          
        RXM0SIDL = %00000000
        RXM0SIDH = %00000000
        
'set up CAN hardware
        BRGCON1 = %00010011      'SJW = 1 Tq, Tq = 40/Fosc
        BRGCON2 = %11111111      'Phase seg 1 = 16 Tq, Sample 3 times
        BRGCON3 = %00000111      'Phase seg 2 = 8 Tq
        
        Set CIOCON.5             'ENDRHI  'recessive drives Tx to Vdd (required if using MCP 2551)
        
        CANCON = %01000000       'Select loopback mode For testing only !!!!
        PIR3 = 0                 'Clear interrupt register
       
        Cls                      'Clear screen
        DelayMS 100    		     ' Wait for LCD to start
        Print At 1,3,"Bobby Garrett's" 
        Print At 2,7,"RGV250"
        Print At 1,22,"  CAN BUS TEST"
        Print At 2,21,"    "
        DelayMS 2000             ' Show message for 2 seconds  
    
        GoTo send

[rcurl]

Bobby-
Thanks for posting your code. I'd be very interested to know how this works out once you have your hardware ready.

My choice of chips was driven by requirements that are probably very different from yours. I must be able to change the main processor to a different type later on, and the selection of PICs that support the CAN bus directly is very limited. Also, I'll have a boatload of remote sensing boards, so cost was an important consideration. The I/O expanders are less than half the cost of the 18F458. That being said, I AM very concerned about the throughput I will be able to get using the SPI bus. I understand that it will be MUCH less than if I had used a PIC that supports CAN directly.

Please keep me posted as your project progresses. As soon as I have something useful, I'll post it too.

Rick

[RGV250]

Hi Rick,
I haven't done a lot to it recently but I thought I would post it as it is as the comms seems to be very reliable, I have had it running at 1mb/s just to see if it was stable and no problems.

As you say in another thread it is not industry standard as I do not need it to be. I do not think it would take a lot of programming to get it that way as most of it is done in the module.
I am not sure about basic commands being written, if you use the PIC's with the CAN module built in then most of it is done for you and it is mainly reading or writing the values in them, the hard bit I found was the configuration and the correct sequence of setting/clearing bits to get the response from the module.
At present I have it on test with 3 nodes, the test code is the same for all 3, there are 3 jumpers on port A to select the node 1 - 8 (once again I will only need 5 (7 max)).
The only real thing I think I will need to look at is the error handling (hopefully never needed) and a transmit on condition change. At present it does all the transmits periodically which are easier to see the test data and will be needed anyway.


Regards,
Bobby

(how do you put the boxes in so the code scrolls in them rather than miles down the page?).

'****************************************************************
'*  Name    : RGV CANBUS TEST                                   *
'*  Author  : Bobby Garrett                                     *
'*  Notice  : Copyright (c) 2005 Bobby Garrett                  *
'*          : All Rights Reserved                               *
'*  Date    : 22/12/2005                                        *
'*  Version : 3 million And 1.0                                 *
'*          :                                                   *
'*  Notes   : CAN bus Set For 125 kb/s                          *
'*          : Uses Philips PCA82C250 transcievers for CANBUS    *
'*          : Display is 4x20 LCD on port D                     *
'*          : Three jumpers on PORTA for node address           *
'****************************************************************  
                               
        Device = 18F448  
        XTAL = 20
        
'Set up PIC registers
        @CONFIG_REQ
        @__CONFIG config1h, OSCS_OFF_1 & HS_OSC_1 & CP_OFF_1L
        @__CONFIG config2l, BOR_ON_2 & BORV_42_2 & PWRT_ON_2
        @__CONFIG config2h, WDT_OFF_2
        @__CONFIG config4l, STVR_ON_4 & LVP_OFF_4 & DEBUG_OFF_4
        
'***********************************************
'* Variable definitions                        *
'***********************************************
' Some of the variables will not be used as the code is generic.
' EG, if this module node is set to 1 by the jumpers then NODE_1_DATA_xx
' variables are not used as they are for received messages and the 
' identifier for the TRANSMIT_DATA_xx will be 1. 

        Dim TRANSMIT_DATA_0 As Byte
        Dim TRANSMIT_DATA_1 As Byte
        Dim TRANSMIT_DATA_2 As Byte
        Dim TRANSMIT_DATA_3 As Byte
        Dim TRANSMIT_DATA_4 As Byte
        Dim TRANSMIT_DATA_5 As Byte
        Dim TRANSMIT_DATA_6 As Byte
        Dim TRANSMIT_DATA_7 As Byte

        Dim NODE_1_DATA_0 As Byte
        Dim NODE_1_DATA_1 As Byte
        Dim NODE_1_DATA_2 As Byte
        Dim NODE_1_DATA_3 As Byte
        Dim NODE_1_DATA_4 As Byte
        Dim NODE_1_DATA_5 As Byte
        Dim NODE_1_DATA_6 As Byte
        Dim NODE_1_DATA_7 As Byte
        
        Dim NODE_2_DATA_0 As Byte
        Dim NODE_2_DATA_1 As Byte
        Dim NODE_2_DATA_2 As Byte
        Dim NODE_2_DATA_3 As Byte
        Dim NODE_2_DATA_4 As Byte
        Dim NODE_2_DATA_5 As Byte
        Dim NODE_2_DATA_6 As Byte
        Dim NODE_2_DATA_7 As Byte
        
        Dim NODE_3_DATA_0 As Byte
        Dim NODE_3_DATA_1 As Byte
        Dim NODE_3_DATA_2 As Byte
        Dim NODE_3_DATA_3 As Byte
        Dim NODE_3_DATA_4 As Byte
        Dim NODE_3_DATA_5 As Byte
        Dim NODE_3_DATA_6 As Byte
        Dim NODE_3_DATA_7 As Byte
        
        Dim NODE_4_DATA_0 As Byte
        Dim NODE_4_DATA_1 As Byte
        Dim NODE_4_DATA_2 As Byte
        Dim NODE_4_DATA_3 As Byte
        Dim NODE_4_DATA_4 As Byte
        Dim NODE_4_DATA_5 As Byte
        Dim NODE_4_DATA_6 As Byte
        Dim NODE_4_DATA_7 As Byte
        
        Dim NODE_5_DATA_0 As Byte
        Dim NODE_5_DATA_1 As Byte
        Dim NODE_5_DATA_2 As Byte
        Dim NODE_5_DATA_3 As Byte
        Dim NODE_5_DATA_4 As Byte
        Dim NODE_5_DATA_5 As Byte
        Dim NODE_5_DATA_6 As Byte
        Dim NODE_5_DATA_7 As Byte
        
        Dim NODE_6_DATA_0 As Byte
        Dim NODE_6_DATA_1 As Byte
        Dim NODE_6_DATA_2 As Byte
        Dim NODE_6_DATA_3 As Byte
        Dim NODE_6_DATA_4 As Byte
        Dim NODE_6_DATA_5 As Byte
        Dim NODE_6_DATA_6 As Byte
        Dim NODE_6_DATA_7 As Byte
        
        Dim NODE_7_DATA_0 As Byte
        Dim NODE_7_DATA_1 As Byte
        Dim NODE_7_DATA_2 As Byte
        Dim NODE_7_DATA_3 As Byte
        Dim NODE_7_DATA_4 As Byte
        Dim NODE_7_DATA_5 As Byte
        Dim NODE_7_DATA_6 As Byte
        Dim NODE_7_DATA_7 As Byte
 
        Dim RX_NODE_NR As Byte    'Temp store for Identifier of received message
        Dim TX_NODE_NR As Byte    'This modules address as set by jumpers on PORTA.
        
        Dim NEW_MESSAGE As Bit    
        
        Dim TIMER1 As TMR1L.Word

        Symbol IPEN = RCON.7
        Symbol TMR1IP = IPR1.0   
        Symbol TMR1IF = PIR1.0  
        Symbol TMR1IE = PIE1.0  
        Symbol GIEH = INTCON.7   
        Symbol GIEL = INTCON.6       
        Symbol TMR1ON = T1CON.0

GoTo INIT

'***********************************************
'* Interrupt service vector initialization     *
'***********************************************
ON_INTERRUPT GoTo INTERRUPT_ROUTINE 'Point to the Interrupt handler

GoTo START                      'Jump over the Interrupt routine
                                  
'****************************************************************
'* Interrupt Service Routine                                    *
'* Determine if it is a timed interrupt or CAN module interrupt *
'* Also the ISR determines whether a Valid message or CAN error *
'* interrupt has occured and then proceeds accordingly          *
'****************************************************************
INTERRUPT_ROUTINE:
        If PIR1.0 = 0 Then GoTo CAN_MODULE_INTERRUPT
        Clear T1CON.0           'Stop timer
         
TIMED_TRANSMIT_ROUTINE: 'If it wasn't the CAN module it must have been the timer Interrupt
        Toggle PORTC.6  'Flash RED LED just to let me know it is doing something
        
'This is just to generate data for testing 
'Normally data wil be written to TRANSMIT_DATA_xx from elsewhere in the program.           
        TRANSMIT_DATA_0 = TRANSMIT_DATA_0 + 1
        If TRANSMIT_DATA_0 = 100 Then TRANSMIT_DATA_0 = 0
        TRANSMIT_DATA_1 = TRANSMIT_DATA_1 + 1
        If TRANSMIT_DATA_1 = 100 Then TRANSMIT_DATA_1 = 0
'Down to here !!!          
  
        TXB0D0 = TRANSMIT_DATA_0'Move data into transmit buffer 0
        TXB0D1 = TRANSMIT_DATA_1
        TXB0D2 = TRANSMIT_DATA_2 
        TXB0D3 = TRANSMIT_DATA_3
        TXB0D4 = TRANSMIT_DATA_4
        TXB0D5 = TRANSMIT_DATA_5
        TXB0D6 = TRANSMIT_DATA_6
        TXB0D7 = TRANSMIT_DATA_7

        CANCON = %00001000      'Normal mode, transmit buffer 0
        TXERRCNT = 0            'Clear TX error counter
        TXB0CON = %00001001     'Start transmition, priority level 1 
WAIT_TX0_OK: If TXB0CON.3 = 1 Then WAIT_TX0_OK 'Loop until TX succesfull
        CANCON = %00000000      'Select CAN normal mode after transmission
        PIR1.0 = 0              'Clear Timer 1 overflow interrupt bit
        TIMER1 = 0              'Re-set timer to zero
        Set T1CON.0             'Re-start timer
        Context Restore         'Exit ISR and re-enable interrupts             
    
CAN_MODULE_INTERRUPT:
        If PIR3.0 = 1 Then GoTo RECEIVE_MSG
        If PIR3.5 = 1 Then GoTo CAN_ERROR

'**********************************************************************
'* CAN Msg Received Routine                                           *
'* This routine is called when a message has been received into RXB0. *
'* The routine reads the Low identifier Byte And Then shifts the bits *  
'* right x 5 to get the number of the node transmitting the message.  *
'**********************************************************************
'It could probably be done better with indirect addressing but I only need 6 nodes !
'It also makes the code more readable and understandable when I look at it in 6 months time.
RECEIVE_MSG:
        Toggle PORTC.7          'Flash GREEN LED to let me know something is happening
        RX_NODE_NR = RXB0SIDL >> 5 'Shift bits right x 5 to determine which node sent
                                   'current message.
        If RX_NODE_NR = 1 Then GoTo MESSAGE_FROM_NODE_1 'go to routine for that message.
        If RX_NODE_NR = 2 Then GoTo MESSAGE_FROM_NODE_2
        If RX_NODE_NR = 3 Then GoTo MESSAGE_FROM_NODE_3
        If RX_NODE_NR = 4 Then GoTo MESSAGE_FROM_NODE_4
        If RX_NODE_NR = 5 Then GoTo MESSAGE_FROM_NODE_5
        If RX_NODE_NR = 6 Then GoTo MESSAGE_FROM_NODE_6
        If RX_NODE_NR = 7 Then GoTo MESSAGE_FROM_NODE_7

MESSAGE_FROM_NODE_1:        
        NODE_1_DATA_0 = RXB0D0  'Copy data in receive buffer as it will be 
        NODE_1_DATA_1 = RXB0D1  'overwritten by Next message
        NODE_1_DATA_2 = RXB0D2       
        NODE_1_DATA_3 = RXB0D3      
        NODE_1_DATA_4 = RXB0D4       
        NODE_1_DATA_5 = RXB0D5      
        NODE_1_DATA_6 = RXB0D6       
        NODE_1_DATA_7 = RXB0D7      
        NEW_MESSAGE = 1         'Set flag to update display
        GoTo DONE
        
MESSAGE_FROM_NODE_2: 
        NODE_2_DATA_0 = RXB0D0  'Copy data in receive buffer as it will be 
        NODE_2_DATA_1 = RXB0D1  'overwritten by Next message
        NODE_2_DATA_2 = RXB0D2       
        NODE_2_DATA_3 = RXB0D3      
        NODE_2_DATA_4 = RXB0D4       
        NODE_2_DATA_5 = RXB0D5      
        NODE_2_DATA_6 = RXB0D6       
        NODE_2_DATA_7 = RXB0D7              
        NEW_MESSAGE = 1         'Set flag to update display
        GoTo DONE
        
MESSAGE_FROM_NODE_3:        
        NODE_3_DATA_0 = RXB0D0  'Copy data in receive buffer as it will be 
        NODE_3_DATA_1 = RXB0D1  'overwritten by Next message
        NODE_3_DATA_2 = RXB0D2       
        NODE_3_DATA_3 = RXB0D3      
        NODE_3_DATA_4 = RXB0D4       
        NODE_3_DATA_5 = RXB0D5      
        NODE_3_DATA_6 = RXB0D6       
        NODE_3_DATA_7 = RXB0D7             
        NEW_MESSAGE = 1         'Set flag to update display
        GoTo DONE
        
MESSAGE_FROM_NODE_4:        
        NODE_4_DATA_0 = RXB0D0  'Copy data in receive buffer as it will be 
        NODE_4_DATA_1 = RXB0D1  'overwritten by Next message
        NODE_4_DATA_2 = RXB0D2       
        NODE_4_DATA_3 = RXB0D3      
        NODE_4_DATA_4 = RXB0D4       
        NODE_4_DATA_5 = RXB0D5      
        NODE_4_DATA_6 = RXB0D6       
        NODE_4_DATA_7 = RXB0D7             
        NEW_MESSAGE = 1         'Set flag to update display
        GoTo DONE
        
MESSAGE_FROM_NODE_5:        
        NODE_5_DATA_0 = RXB0D0  'Copy data in receive buffer as it will be 
        NODE_5_DATA_1 = RXB0D1  'overwritten by Next message
        NODE_5_DATA_2 = RXB0D2       
        NODE_5_DATA_3 = RXB0D3      
        NODE_5_DATA_4 = RXB0D4       
        NODE_5_DATA_5 = RXB0D5      
        NODE_5_DATA_6 = RXB0D6       
        NODE_5_DATA_7 = RXB0D7            
        NEW_MESSAGE = 1         'Set flag to update display
        GoTo DONE
        
MESSAGE_FROM_NODE_6:        
        NODE_6_DATA_0 = RXB0D0  'Copy data in receive buffer as it will be 
        NODE_6_DATA_1 = RXB0D1  'overwritten by Next message
        NODE_6_DATA_2 = RXB0D2       
        NODE_6_DATA_3 = RXB0D3      
        NODE_6_DATA_4 = RXB0D4       
        NODE_6_DATA_5 = RXB0D5      
        NODE_6_DATA_6 = RXB0D6       
        NODE_6_DATA_7 = RXB0D7             
        NEW_MESSAGE = 1         'Set flag to update display
        GoTo DONE
          
MESSAGE_FROM_NODE_7:        
        NODE_7_DATA_0 = RXB0D0  'Copy data in receive buffer as it will be 
        NODE_7_DATA_1 = RXB0D1  'overwritten by Next message
        NODE_7_DATA_2 = RXB0D2       
        NODE_7_DATA_3 = RXB0D3      
        NODE_7_DATA_4 = RXB0D4       
        NODE_7_DATA_5 = RXB0D5      
        NODE_7_DATA_6 = RXB0D6       
        NODE_7_DATA_7 = RXB0D7            
        NEW_MESSAGE = 1         'Set flag to update display
        GoTo DONE 
DONE:   
        COMSTAT = 0             'Clear CAN comminication status register
        RXB0CON = %00100000     'Set RXB0CON for next message   
        PIR3 = 0                'Clear CAN bus error interrupt bits   
        Context Restore         'Exit ISR and re-enable interrupts       

'*******************************************************************
'* CAN Error routine                                               *
'* At present this routine only places some registers on the LCD   *
'* turns on LED and halts program for diagnosing problem.          *
'*******************************************************************
CAN_ERROR:
        Cls           'Clear screen
        PORTD.1 = 1   'Turn on RED LED for CAN error
        Print At 1,1, "CAN error"
        Print At 2,1, Dec TXERRCNT
        Print At 2,11, Dec RXERRCNT
        Print At 1,21, Dec COMSTAT
        Print At 1,31, Dec PIR3 
        Stop
    
'***********************************************
'* Start of Main Code                          *
'***********************************************
START:
'Set up priority interrupts.
        IPEN = 1                ' Enable priority interrupts.
        TMR1IP = 1              ' Set Timer1 as a high priority interrupt source
        TMR1IF = 0              ' Clear the Timer1 interrupt flag
        TMR1IE = 1              ' Enable Timer1 interrupts
        GIEH = 1                ' Set the global interrupt enable bits

'Send start up message to LCD        
        Cls                               'Clear screen
        DelayMS 100    		              ' Wait for LCD to start
        Print At 1,1, "  Bobby Garrett's" 'Show start up message
        Print At 2,1, "      RGV250"
        Print At 1,21,"   CAN BUS TEST"
        Print At 2,21,"      NODE ",Dec TX_NODE_NR 'Show node number       
        DelayMS 2000                      ' Show message for 2 seconds         
        Cls                     'Clear screen
                  
'Set up TIMER1                            
        T1CON = %10110000       'Timer1 - 1:8 prescaler and act as timer
        TIMER1 = 0              'Zero Timer
        T1CON.0 = 1             'Start Timer running
        PIR1.0 = 0              'Clear timer 1 overflow bit
        PIE1 = 1                'Enable Timer1 interrupt

'***********************************************
'* Main program LOOP                           *
'***********************************************
LOOP:
        COMSTAT = 0             'Clear CAN comminication status register.
        INTCON = %00000000      'Turn off interrupts
'Normal code routines go between here
'Probably try using "Include" here so the CAN code never needs changeing. 
        If NEW_MESSAGE = 1 Then GoSub DISPLAY 'Only write to display if new message
'And here 
        INTCON = %11000000      'Turn interrupts back on
        GoTo LOOP
DISPLAY:
        Print At 1,1, "1<", Dec NODE_1_DATA_0,"  "
        Print At 2,1, "1<", Dec NODE_1_DATA_1,"  "
        Print At 1,7, "2<", Dec NODE_2_DATA_0,"  "
        Print At 2,7, "2<", Dec NODE_2_DATA_1,"  "
        Print At 1,13, "3<", Dec NODE_3_DATA_0,"  "
        Print At 2,13, "3<", Dec NODE_3_DATA_1,"  "
        Print At 1,21, "4<", Dec NODE_4_DATA_0,"  "
        Print At 2,21, "4<", Dec NODE_4_DATA_1,"  "
        Print At 1,27, "5<", Dec NODE_5_DATA_0,"  "
        Print At 2,27, "5<", Dec NODE_5_DATA_1,"  "
 '   Print At 1,29, "6<", Dec NODE_6_DATA_0,"  "     'Not used due to screen size
 '   Print At 2,29, "6<", Dec NODE_6_DATA_1,"  "     'also I do not have the nodes
 '   Print At 1,31, "7<", Dec NODE_7_DATA_0,"  "     'attached at present
 '   Print At 2,31, "7<", Dec NODE_7_DATA_1,"  "
        Print At 1,33, "T>", Dec TRANSMIT_DATA_0,"  "
        Print At 2,33, "T>", Dec TRANSMIT_DATA_1,"  "
        NEW_MESSAGE = 0
        Return

'******************************************************
'* PIC Initialization                                 *
'* Most of the CAN module registers are here Whether  *
'* used Or Not so I don't have to type them in again. *
'******************************************************       
INIT:
        ALL_DIGITAL = True      'Set all I/O to digital
'Set port direction On power up Or after reset       
        TRISA.0 = 1             'Set port direction - NODE address bit 0
        TRISA.1 = 1             'Set port direction - NODE address bit 1
        TRISA.2 = 1             'Set port direction - NODE address bit 2
        
'Set port direction for CAN I/O        
'This is important, Proton does not set the port direction of the CAN I/O pins !!         
        TRISB.2 = 0             'Set port direction - CANTx pin as output
        TRISB.3 = 1             'Set port direction - CANRx pin as input 
        
'Set port direction On power up Or after reset        
        TRISC.6 = 0             'Set port direction - LED for diagnostics
        TRISC.7 = 0             'Set port direction - LED for diagnostics
        TRISD.1 = 0             'Set port direction - LED for diagnostics
        
'Set state of port on power up or after reset
        PORTC.6 = 0             'Initialise output as off
        PORTC.7 = 0             'Initialise output as off
        PORTD.1 = 0             'Initialise output as off
 
'Determine node address
        PORTA = 0               'Clear PORTA
        TX_NODE_NR = PORTA & %00000111 '"AND" to filter out unwanted bits 
        
'CAN MODULE          
'Set up the CAN module               
        CANCON = %10000000      'Select CAN config mode
        TXB0CON = 0             'Clear transmit buffer 0 control register
          
'set up CAN hardware
        BRGCON1 = %00000011     'SJW = 1 Tq, Tq = 4/Fosc
        BRGCON2 = %11101100     'Phase seg 1 = 6 x Tq, Prop = 5 x tq, Sample 3 times
        BRGCON3 = %00000111     'Phase seg 2 = 8 x Tq
        Clear CIOCON.5          'ENDRHI  'recessive drives Tx to Vdd (required if using MCP 2551)
        
        TXB0DLC  = %00001000    'RTR bit cleared, 8 byte data length
        RXB0DLC  = %00001000    '8 byte data length
       
'Set low identifier bits to node address set by jumpers on PORTA
'Only low byte used
        TXB0SIDH = %00000000    'Set Identifier bits
        TX_NODE_NR = TX_NODE_NR << 5 'Shift left before AND ing
        TXB0SIDL = TX_NODE_NR & %11100000  'Set Identifier bits
        TX_NODE_NR = TX_NODE_NR >> 5 'Shift back for start up message
           
        RXM0SIDH = %00000000    'Set Receive mask 0 bits
        RXM0SIDL = %00000000    'Set Receive mask 0 bits
         
        RXM1SIDH = %00000000    'Set Receive mask 1 bits
        RXM1SIDL = %00000000    'Set Receive mask 1 bits   
        
        RXF0SIDH = %00000000    'Set Receive filter 0 bits
        RXF0SIDL = %00000000    'Set Receive filter 0 bits    
        
        RXF1SIDH = %00000000    'Set Receive filter 1 bits
        RXF1SIDL = %00000000    'Set Receive filter 1 bits    
        
        COMSTAT = 0             'Clear CAN comminication status register.
        CANCON = %00000000      'Select CAN normal mode
        RXB0CON = %00100000     'Receive only valid messages with standard identifier
        PIR3 = 0                'Clear Peripheral interrupt register 3
        PIE3 = %00100001        'Enable selected Peripheral interrupts
        
        TXERRCNT = 0            'Clear Transmit error counter
        RXERRCNT = 0            'Clear Receive error counter
        
        TXB0D0   = 0            'Clear Transmit buffer 0 bytes
        TXB0D1   = 0   
        TXB0D2   = 0   
        TXB0D3   = 0   
        TXB0D4   = 0    
        TXB0D5   = 0   
        TXB0D6   = 0   
        TXB0D7   = 0 
        
        TXB1D0   = 0            'Clear Transmit buffer 1 bytes
        TXB1D1   = 0
        TXB1D2   = 0 
        TXB1D3   = 0 
        TXB1D4   = 0 
        TXB1D5   = 0 
        TXB1D6   = 0 
        TXB1D7   = 0 
        
        TXB2D0   = 0            'Clear Transmit buffer 2 bytes
        TXB2D1   = 0
        TXB2D2   = 0 
        TXB2D3   = 0 
        TXB2D4   = 0 
        TXB2D5   = 0 
        TXB2D6   = 0
        TXB2D7   = 0
        
        RXB0D0   = 0            'Clear Receive buffer 0 bytes
        RXB0D1   = 0
        RXB0D2   = 0
        RXB0D3   = 0
        RXB0D4   = 0
        RXB0D5   = 0
        RXB0D6   = 0
        RXB0D7   = 0
        
        RXB1D0   = 0            'Clear Receive buffer 1 bytes
        RXB1D1   = 0
        RXB1D2   = 0
        RXB1D3   = 0
        RXB1D4   = 0
        RXB1D5   = 0
        RXB1D6   = 0
        RXB1D7   = 0
        
        TRANSMIT_DATA_0 = 0     'Clear Variables
        TRANSMIT_DATA_1 = 0
        TRANSMIT_DATA_2 = 0
        TRANSMIT_DATA_3 = 0
        TRANSMIT_DATA_4 = 0
        TRANSMIT_DATA_5 = 0
        TRANSMIT_DATA_6 = 0
        TRANSMIT_DATA_7 = 0        
        
        NODE_1_DATA_0 = 0       'Clear Variables
        NODE_1_DATA_1 = 0 
        NODE_1_DATA_2 = 0 
        NODE_1_DATA_3 = 0 
        NODE_1_DATA_4 = 0 
        NODE_1_DATA_5 = 0 
        NODE_1_DATA_6 = 0 
        NODE_1_DATA_7 = 0 
        
        NODE_2_DATA_0 = 0       'Clear Variables
        NODE_2_DATA_1 = 0
        NODE_2_DATA_2 = 0
        NODE_2_DATA_3 = 0
        NODE_2_DATA_4 = 0
        NODE_2_DATA_5 = 0
        NODE_2_DATA_6 = 0
        NODE_2_DATA_7 = 0
         
        NODE_3_DATA_0 = 0       'Clear Variables
        NODE_3_DATA_1 = 0
        NODE_3_DATA_2 = 0
        NODE_3_DATA_3 = 0
        NODE_3_DATA_4 = 0
        NODE_3_DATA_5 = 0
        NODE_3_DATA_6 = 0
        NODE_3_DATA_7 = 0
         
        NODE_4_DATA_0 = 0       'Clear Variables
        NODE_4_DATA_1 = 0 
        NODE_4_DATA_2 = 0 
        NODE_4_DATA_3 = 0 
        NODE_4_DATA_4 = 0 
        NODE_4_DATA_5 = 0 
        NODE_4_DATA_6 = 0 
        NODE_4_DATA_7 = 0 
        
        NODE_5_DATA_0 = 0       'Clear Variables
        NODE_5_DATA_1 = 0 
        NODE_5_DATA_2 = 0 
        NODE_5_DATA_3 = 0 
        NODE_5_DATA_4 = 0 
        NODE_5_DATA_5 = 0 
        NODE_5_DATA_6 = 0 
        NODE_5_DATA_7 = 0 
  
        NODE_6_DATA_0 = 0       'Clear Variables
        NODE_6_DATA_1 = 0 
        NODE_6_DATA_2 = 0   
        NODE_6_DATA_3 = 0  
        NODE_6_DATA_4 = 0  
        NODE_6_DATA_5 = 0 
        NODE_6_DATA_6 = 0    
        NODE_6_DATA_7 = 0   
  
        NODE_7_DATA_0 = 0       'Clear Variables
        NODE_7_DATA_1 = 0
        NODE_7_DATA_2 = 0  
        NODE_7_DATA_3 = 0  
        NODE_7_DATA_4 = 0 
        NODE_7_DATA_5 = 0
        NODE_7_DATA_6 = 0  
        NODE_7_DATA_7 = 0  
       
        RX_NODE_NR = 0

'Set Diplay up
        Declare LCD_TYPE 0 
        Declare LCD_INTERFACE 4
        Declare LCD_LINES 2
        LCD_DTPIN = PORTD.4
        LCD_ENPIN = PORTD.2
        LCD_RSPIN = PORTD.3      
       
        If TX_NODE_NR > 0 And TX_NODE_NR < 8 Then GoTo START 'Check node address is set

'If the program has got to here then the node address has not been read properly (1 - 7)
'Put message on screen and Flash LED, halt program.

        Cls                               'Clear screen
        Print At 1,1, "NODE ERROR - ",Dec TX_NODE_NR 
NODE_ERROR:                                                     
        Toggle PORTD.1   'Flash RED LED for Node address error 
        DelayMS 1000
        GoTo NODE_ERROR                                            
        Stop

[RGV250]

Rick,
If you do give it a go and want to try different speeds below are the settings needed, if you need other speeds http://www.kvaser.com/ has a good calculator, just use the MCP2510 settings and convert to binary.

100K
BRGCON1 = %00000011
BRGCON2 = %10111111
BRGCON3 = %00000111

1M
BRGCON1 = %00000000
BRGCON2 = %10001001
BRGCON3 = %00000100

Regards,
Bobby

[RMUTR]

Hi.

PIC18F4680 CAN Code not work.Please Help?

CAN Message Transmitt Problem.(or ECAN Code Conversion)

Regards.
Thanks.
RMUTR

[RGV250]

Hi,
Need a bit more to go on than that.

Regards,
Bobby