 |
 |
| View previous topic :: View next topic |
| Author |
Message |
baklou
Joined: 10 Jan 2014
Posts: 22
|
| Another CAN Bus Problem ...! [SOLVED] |
 Posted: Tue Jan 14, 2014 7:21 am |
 |
|
Hello everybody,
I'm trying to make a CAN bus communication between microcontrollers, and to do that, I decided to make a simple communication between two boards, but unfortunately, I never be able to see it work fine...
I'll detail every thing I did, I do...
First, I'm compiling with PCWH v. 4.124 on two PIC18F46K80.
So... here is my board :
[img]
http://imageshack.com/a/img5/6392/d00z.jpg
[/img]
and here is the schematic :
[img]
http://imageshack.com/a/img194/5991/2xhf.jpg
[/img]
each board connected respectively by the CANH and CANL pins of the transceiver...
Before posting this thread, I've been on all others which speaks about CAN bus problem ...
I first saw this post http://www.ccsinfo.com/forum/viewtopic.php?t=20106 and then try to make it work in loopback mode. It worked fine...
I just precise that I'm using C6 and C7 pins to make my CAN bus. So I use the fuse "CANC" and I initialize C6 as output and C7 as input with :
| Code: |
set_tris_c((*0xF94 & 0xBF ) | 0x80); // 0xF94 is the physical adress of TRISC register.
|
and then, I tried to make this test run :
http://www.ccsinfo.com/forum/viewtopic.php?t=29627&start=3
changing a little bit of code...but without any success...
I've try with extended IDs, normal IDs (using and changing the 3rd parameter of can_set_id() function), nothing works.
here is my code :
| Code: |
#include <18F46K80.h>
#fuses NOPROTECT, PUT, BROWNOUT, NOWDT, NOPLLEN, CANC
#use delay(clock=8000000)
#use rs232(baud=9600, xmit=PIN_D6, rcv=PIN_D7, parity=N, bits=8)
#include <can-18xxx8.c>
#define BOARD1_ID 24
#define BOARD2_ID 25
#define BOUTON PIN_A0 // Bouton poussoir
// Uncomment this line to compile code for Board #1.
// Comment it out to compile for Board #2.
#define BOARD1 1
//======================================
void main()
{
struct rx_stat rxstat;
int32 rx_id;
int32 tx_id;
int8 rx_len;
int8 buffer[8];
set_tris_a(*0xF92 | 0x01); // I configure my I/O on PortA to define "BOUTON" as input (cabled with a pull up)
can_init();
#ifdef BOARD1 // For Board #1
while(1)
{
while(input(BOUTON));
buffer[0] = "T"; // I fill the buffer automatically
// Transmit it to board #2.
can_putd(BOARD2_ID, buffer, 1, 1, 1, 0);
printf("\r\nBUFFER:%c\r\n", buffer[0]);
buffer[0] = 0; // Clear the buffer byte
// Wait for the char to be echoed back.
while(!can_kbhit());
if(can_getd(rx_id, buffer, rx_len, rxstat))
{
if(rx_id == BOARD1_ID) // Is it for this board ?
{
putc(buffer[0]); // If so, display the char
}
}
}
#else // For Board #2
while(1)
{
if(can_kbhit()) // Message available ?
{
printf("\r\nMESSAGE!!\r\n");
// If so, get the message.
if(can_getd(rx_id, buffer, rx_len, rxstat))
{
if(rx_id == BOARD2_ID) // Is it for this board ?
{
// If so, echo back the character.
can_putd(BOARD1_ID, buffer, 1, 1, 1, 0);
}
}
}
}
#endif
}
|
and my "can_init()" function :
| Code: |
void can_init(void) {
can_set_mode(CAN_OP_CONFIG); //must be in config mode before params can be set
can_set_baud();
RXB0CON=0;
RXB0CON.rxm=CAN_RX_VALID;
RXB0CON.rxb0dben=CAN_USE_RX_DOUBLE_BUFFER;
RXB1CON=RXB0CON;
CIOCON.endrhi=CAN_ENABLE_DRIVE_HIGH;
CIOCON.cancap=CAN_ENABLE_CAN_CAPTURE;
CIOCON.tx2src=CAN_CANTX2_SOURCE; //added 3/30/09 for PIC18F6585/8585/6680/8680
CIOCON.tx2en=CAN_ENABLE_CANTX2; //added 3/30/09 for PIC18F6585/8585/6680/8680
can_set_id(RX0MASK, CAN_MASK_ACCEPT_ALL, CAN_USE_EXTENDED_ID); //set mask 0
can_set_id(RX0FILTER0, 0, CAN_USE_EXTENDED_ID); //set filter 0 of mask 0
can_set_id(RX0FILTER1, 0, CAN_USE_EXTENDED_ID); //set filter 1 of mask 0
can_set_id(RX1MASK, CAN_MASK_ACCEPT_ALL, CAN_USE_EXTENDED_ID); //set mask 1
can_set_id(RX1FILTER2, 0, CAN_USE_EXTENDED_ID); //set filter 0 of mask 1
can_set_id(RX1FILTER3, 0, CAN_USE_EXTENDED_ID); //set filter 1 of mask 1
can_set_id(RX1FILTER4, 0, CAN_USE_EXTENDED_ID); //set filter 2 of mask 1
can_set_id(RX1FILTER5, 0, CAN_USE_EXTENDED_ID); //set filter 3 of mask 1
//set_tris_b((*0xF93 & 0xFB ) | 0x08); //b3 is in, b2 is out
set_tris_c((*0xF94 & 0xBF ) | 0x80);
//TRISC &= 0xBF;
//TRISC |= 0x80;
can_set_mode(CAN_OP_NORMAL);
}
|
and CAN_USE_EXTENDED_ID is define as TRUE.
I've checked the value of my two resistors, they are 120 ohms each.
Last thing, but not least... I can't see any signal on my 40 Mhz scope. Neither on the pin of the microcontroller, neither on the MCP2551 pins, neither on the bus itself. Is it normal ?
For the CAN bus rate, I've let the defaults values, so if I'm right, it' a 125 kbps bus...so I could read the signal normally ... no ?
and to finish, contrary to the schematic of the board, I decided to connect RS pin of the transceiver directly to the ground in spite of the B0 pin of the microcontroller. I did it to be sure to have a low level on the pin. The doc says to put a resistor between, but it don't clearly explain which value to put ... and as I saw it on other projects, I wired it directly to the ground.
Thanks to every people who could help me ... Sorry to come again with a CAN bus problem, but mine seems to really be desperate...
Greg
Last edited by baklou on Mon Feb 24, 2014 4:01 am; edited 1 time in total |
|
 |
baklou
Joined: 10 Jan 2014
Posts: 22
|
|
| Posted: Tue Jan 14, 2014 8:25 am |
|
|
Just a rectification (to reply to myself ^^).... I changed the transceiver associated to board#1, and suddenly, I can clearly see the signal, on the transceiver pins, on the CANH, CANH signal which is clearly the invert of the CANL signal. The signal runs until the microcontroller board #2 but....
I still have no response from board #2 !!!
I continue on my way... |
|
|
baklou
Joined: 10 Jan 2014
Posts: 22
|
|
| Posted: Wed Jan 15, 2014 4:21 am |
|
|
Hello everybody,
I'm coming again to look for advice... my two boards still don't communicate at all and I don't know why.
I can clearly read CAN signal until the CANRX pin of the microcontroller, but the RX buffer still empty. is it because of the ID settings ? extended ID or normal ID ? I've try with both of them (modifying the CAN_USE_EXTENDED_ID definition to FALSE, and put it in the can_putd() function also) but nothing changes.
The signal is coming until the microcontroller, so I deduce that it's a programming problem...but I can't understand why the RX buffer of the board #2 don't receive the message....
If someone can help me ... |
|
|
baklou
Joined: 10 Jan 2014
Posts: 22
|
|
| Posted: Wed Jan 15, 2014 7:57 am |
|
|
I decided to modify my library and accept all messages, even those with errors. So I modified the receiver buffer 0 mode (rxm bits in RXB0CON register) into CAN_RX_ALL mode ("Receive all messages (including those with errors); filter criteria is ignored" p.406).
And suddenly... It works !!
So my idea was correct, my problem comes from my filters and masks settings ...:
| Code: |
void can_init(void) {
can_set_mode(CAN_OP_CONFIG); //must be in config mode before params can be set
can_set_baud();
RXB0CON=0;
RXB0CON.rxm=CAN_RX_VALID; // That's here I put "CAN_RX_ALL" value to success....
RXB0CON.rxb0dben=CAN_USE_RX_DOUBLE_BUFFER;
RXB1CON=RXB0CON;
CIOCON.endrhi=CAN_ENABLE_DRIVE_HIGH;
CIOCON.cancap=CAN_ENABLE_CAN_CAPTURE;
CIOCON.tx2src=CAN_CANTX2_SOURCE; //added 3/30/09 for PIC18F6585/8585/6680/8680
CIOCON.tx2en=CAN_ENABLE_CANTX2; //added 3/30/09 for PIC18F6585/8585/6680/8680
can_set_id(RX0MASK, CAN_MASK_ACCEPT_ALL, CAN_USE_EXTENDED_ID); //set mask 0
can_set_id(RX0FILTER0, 0, CAN_USE_EXTENDED_ID); //set filter 0 of mask 0
can_set_id(RX0FILTER1, 0, CAN_USE_EXTENDED_ID); //set filter 1 of mask 0
can_set_id(RX1MASK, CAN_MASK_ACCEPT_ALL, CAN_USE_EXTENDED_ID); //set mask 1
can_set_id(RX1FILTER2, 0, CAN_USE_EXTENDED_ID); //set filter 0 of mask 1
can_set_id(RX1FILTER3, 0, CAN_USE_EXTENDED_ID); //set filter 1 of mask 1
can_set_id(RX1FILTER4, 0, CAN_USE_EXTENDED_ID); //set filter 2 of mask 1
can_set_id(RX1FILTER5, 0, CAN_USE_EXTENDED_ID); //set filter 3 of mask 1
set_tris_c((*0xF94 & 0xBF ) | 0x80);
can_set_mode(CAN_OP_NORMAL);
}
|
I put it, if (maybe..) someone knows why my masks and filter aren't well configured...
(Yes, yes, you don't hallucinate...I'm talking to myself ...and It seems to work well ... ) |
|
|
PCM programmer
Joined: 06 Sep 2003
Posts: 21708
|
|
| Posted: Wed Jan 15, 2014 12:45 pm |
|
|
| Quote: | #include <18F46K80.h>
#fuses NOPROTECT, PUT, BROWNOUT, NOWDT, NOPLLEN, CANC
#use delay(clock=8000000)
#use rs232(baud=9600, xmit=PIN_D6, rcv=PIN_D7, parity=N, bits=8)
#include <can-18xxx8.c> |
There is a Can bus driver designed for the "80" series PICs:
c:\program files\picc\drivers\can-18f4580.c |
|
|
baklou
Joined: 10 Jan 2014
Posts: 22
|
|
| Posted: Wed Jan 15, 2014 6:03 pm |
|
|
ho really ?!....and do you think this is why I can't receive my messages on my second board ??
I'll check the difference between the two different libraries later. Thank you for answering to me... |
|
|
baklou
Joined: 10 Jan 2014
Posts: 22
|
|
| Posted: Fri Jan 17, 2014 4:19 am |
|
|
I've tried with this new one library...but nothing different. It still work with "CAN_RX_ALL" RX mode, but nothing with "CAN_RX_VALID" RXB0CON state.
In conclusion, this new one library doesn't solve my problem, and seems to function as the can-18xxx8 library....So it's my masks and/or my filters which are badly configured. Or my sent message which is not correctly sent...
I'm totally lost...I still investigate it.
Greg |
|
|
baklou
Joined: 10 Jan 2014
Posts: 22
|
|
| Posted: Tue Jan 21, 2014 1:17 am |
|
|
| Just to up... I still be totally lost...If someone has an idea. Thanks |
|
|
PCM programmer
Joined: 06 Sep 2003
Posts: 21708
|
|
| Posted: Tue Jan 21, 2014 1:22 am |
|
|
| Quote: | I changed the transceiver associated to board#1, and suddenly, I can
clearly see the signal, on the transceiver pins, on the CANH, CANH signal
which is clearly the invert of the CANL signal. The signal runs until the
microcontroller board #2 but....
I still have no response from board #2 !!!
|
What about the transceiver on board #1 ? Did you check it out in the
same way ? I mean, prove that board #1 has output on CANH and CANL ?
------------
Also, just a minute here. I just took a look at your schematic again.
This is a repeat of another thread. You have left off all kinds of
required capacitors and power and ground connections from the PIC.
- Vdd and Vss on pins 32 and 31 are not connected to anything.
- You're missing the required 10 uF / 16v ceramic chip capacitor on the
Vcap pin. (Not aluminum electrolytic).
Section 2 of the 18F46K80 data sheet explains all this stuff in detail.
I don't think we can do anything more until you get all this stuff fixed. |
|
|
baklou
Joined: 10 Jan 2014
Posts: 22
|
|
| Posted: Tue Jan 21, 2014 3:57 am |
|
|
I can clearly see the CAN signal on the transceiver #1, until the CANRX pin of board #2, so my board and transceiver #1 works well. I can post the screenshots of my scope of the signal also...if it's necessary.
My Vdd and Vss pins are already connected on pins 11 and 12, I did think I had to also connect the 31 an 32 pins...
I wired my microcontroller for microcontroller programmation, that's why I missed required capacitors, it's true ...
I will fix it as soon as possible...
Thank you again. |
|
|
baklou
Joined: 10 Jan 2014
Posts: 22
|
|
| Posted: Tue Feb 18, 2014 2:08 am |
|
|
Hello,
I come back with my CAN bus after many research. I rewire my PICs as there :
I rewired the two Vss and Vdd pins on C3 and C17 capacitors, and L2 self. I also rewired the MCLR and a 0.1uF capacitor to ground on pin6.
I closely read this post:
http://www.ccsinfo.com/forum/viewtopic.php?t=48915&highlight=18f46k80
and I still got the sames troubles...
My PICs works finely on loopback mode each one. On normal mode, they works finely but only CAN_RX_ALL mode, not in CAN_RX_VALID mode.
I've try with a 8 bytes buffer, and the ID, the datas and I got it:
What does mean a valid message ? Why my "unvalid" messages comes perfectly but they aren't considerate as "valid"..?
I'm ready to make a new test board so that I don't understand nothing......
Here is my code :
| Code: |
#include <loop2.h>
#fuses HSM, NOPROTECT, PUT, BROWNOUT, NOWDT, NOPLLEN, CANC, SOSC_DIG, NOIESO, NOFCMEN
#use delay(clock=8000000)
#use rs232(baud=9600, xmit=PIN_D6, rcv=PIN_D7, parity=N, bits=8)
#include <can-18F4580.c>
#define BOARD1_ID 24
#define BOARD2_ID 25
#define BOUTON PIN_A0 // Bouton poussoir
#define LED0 PIN_B3 // LED verte de droite, coté connecteur RJ11
#define LED1 PIN_B2 // LED rouge du milieu du boitier
#define LED2 PIN_B1 // LED verte de gauche, coté connecteur RS232
// Uncomment this line to compile code for Board #1.
// Comment it out to compile for Board #2.
//#define BOARD1 1
//======================================
void main()
{
struct rx_stat rxstat;
int32 rx_id;
int32 tx_id;
int8 rx_len;
int8 buffer[8];
printf("\r\n Start !\r\n");
set_tris_a(*0xF92 | 0x01);
set_tris_b((*0xF93 | 0x0F)); //b0, b1 b2 and b3 are out
can_init();
output_low(LED0);
output_low(LED1);
output_low(LED2);
#ifdef BOARD1 // For Board #1
while(1)
{
delay_ms(2500);
strcpy(buffer, "87654321"); // Wait for a character
// Transmit it to board #2.
if(can_putd(BOARD2_ID, buffer, 8, 1, 1, 0))
{
printf("\r\nBUFFER:%s\r\n", buffer);
}
}
#else // For Board #2
while(1)
{
output_low(LED0);
output_low(LED1);
output_low(LED2);
delay_ms(2500);
if(can_kbhit()) // Message available ?
{
// If so, get the message.
if(can_getd(rx_id, buffer, rx_len, rxstat))
{
if(rx_id == BOARD2_ID) // Is it for this board ?
{
// If so, echo back the character.
output_high(LED0);
output_high(LED1);
output_high(LED2);
printf("\r\nBUFFER:%s\r\n",buffer);
printf("\r\nID:%ld\r\n",rx_id);
printf("\r\nSIZE:%d\r\n",rx_len);
//can_putd(BOARD1_ID, buffer[0], 1, 1, 1, 0);
}
}
}
}
#endif
}
|
If someone knows where my problem comes from...Thank U
Greg |
|
|
baklou
Joined: 10 Jan 2014
Posts: 22
|
|
| Posted: Tue Feb 18, 2014 9:15 am |
|
|
It's me, again and again. I checked the rxstat structure that contains the function can_getd(...). It contains lot of informations, as which filter is used, which buffer is used, and many more. The last one is a boolean field that tell if it's an invalid ID or not. And it is !
[img]
http://imageshack.com/a/img31/4952/lthp.jpg
[/img]
So it definitely comes from the IDs. But as you can see on the picture, The board ID is correct (here I put 25 for the reception Board). I use extended IDs, as told in the "ext" field of this rxstat structure. But changing standard or extended IDs does not really solve my problem.
I know that IDs are not just integer put into a variable....can_put_id() and can_get_id() has been implemented, so it's probably more complicated than just put a number into a variable....So does it come from the can_set_id() function ? can_get_id() function ? extended or standard ? I go back to my crazy CAN test board to still investigate...
See you soon... |
|
|
PCM programmer
Joined: 06 Sep 2003
Posts: 21708
|
|
| Posted: Tue Feb 18, 2014 11:10 am |
|
|
One problem you have is this one:
| Quote: |
int8 buffer[8];
strcpy(buffer, "87654321");
|
strcpy puts a 0x00 byte at the end of the copied characters, because
a string in C requires a 0x00 byte to mark the end of the string.
So your code above is over-writing the next variable assigned by
the compiler, which is causing strange problems. We can see this
in your printout, with missing first characters.
If you want to put an 8-byte string into your buffer, you need to increase
the buffer size to 9 bytes to hold the 0x00 byte at the end. Example:
I will try to look at the rest of your problems. I notice that you have
changed several things from my "two board" test program here
http://www.ccsinfo.com/forum/viewtopic.php?t=29627&start=7
and you have changed the can_init() routine in can-18F4580.c.
I mean, you changed can-18F4580.c in ways that you didn't mention
in your posts. This may be causing part of your problems.
I will look into it. |
|
|
baklou
Joined: 10 Jan 2014
Posts: 22
|
|
| Posted: Wed Feb 19, 2014 1:31 am |
|
|
Thank you for the over-writing issue, I totally missed it. I changed a lot of things in your "two boards" test program because the communication doesn't work even between board #1 and #2 in the first "way" to go. So I focused on a "simple" communication, so just board #1 to board #2.
About the CAN library, I just modified the can_init() function, and more particularly the "CAN_RX_MODE", and add the I/O settings in this function
| Code: |
set_tris_c((*0xF94 & 0xBF ) | 0x80);
|
So finally, here is my can_init() routine, which I didn't change a lot :
| Code: |
void can_init(void) {
can_set_mode(CAN_OP_CONFIG); //must be in config mode before params can be set
can_set_baud();
curfunmode=CAN_FUN_OP_LEGACY;
// RXB0CON
// filthit0=0
// jtoff=0
// rxb0dben=1 buffer zero will overflow into buffer one
// rxrtrro=0
// rxm1:0=0 will receive all valid IDs
RXB0CON=0;
RXB0CON.rxm=CAN_RX_ALL;
RXB0CON.rxb0dben=CAN_USE_RX_DOUBLE_BUFFER;
RXB1CON=RXB0CON;
CIOCON.endrhi=CAN_ENABLE_DRIVE_HIGH;
CIOCON.cancap=CAN_ENABLE_CAN_CAPTURE;
CIOCON.tx2src=CAN_CANTX2_SOURCE; //added for PIC18F6585/8585/6680/8680
CIOCON.tx2en=CAN_ENABLE_CANTX2; //added for PIC18F6585/8585/6680/8680
can_set_id(RX0MASK, CAN_MASK_ACCEPT_ALL, CAN_USE_EXTENDED_ID); //set mask 0
can_set_id(RXFILTER0, 0, CAN_USE_EXTENDED_ID); //set filter 0 of mask 0
can_set_id(RXFILTER1, 0, CAN_USE_EXTENDED_ID); //set filter 1 of mask 0
can_set_id(RX1MASK, CAN_MASK_ACCEPT_ALL, CAN_USE_EXTENDED_ID); //set mask 1
can_set_id(RXFILTER2, 0, CAN_USE_EXTENDED_ID); //set filter 0 of mask 1
can_set_id(RXFILTER3, 0, CAN_USE_EXTENDED_ID); //set filter 1 of mask 1
can_set_id(RXFILTER4, 0, CAN_USE_EXTENDED_ID); //set filter 2 of mask 1
can_set_id(RXFILTER5, 0, CAN_USE_EXTENDED_ID); //set filter 3 of mask 1
// set dynamic filters
can_set_id(RXFILTER6, 0, CAN_USE_EXTENDED_ID);
can_set_id(RXFILTER7, 0, CAN_USE_EXTENDED_ID);
can_set_id(RXFILTER8, 0, CAN_USE_EXTENDED_ID);
can_set_id(RXFILTER9, 0, CAN_USE_EXTENDED_ID);
can_set_id(RXFILTER10, 0, CAN_USE_EXTENDED_ID);
can_set_id(RXFILTER11, 0, CAN_USE_EXTENDED_ID);
can_set_id(RXFILTER12, 0, CAN_USE_EXTENDED_ID);
can_set_id(RXFILTER13, 0, CAN_USE_EXTENDED_ID);
can_set_id(RXFILTER14, 0, CAN_USE_EXTENDED_ID);
can_set_id(RXFILTER15, 0, CAN_USE_EXTENDED_ID);
set_tris_c((*0xF94 & 0xBF ) | 0x80); // C7 as input and C6 as output
can_set_mode(CAN_OP_NORMAL);
}
|
I know exchanging files here is not allowed, so don't ask to you to give me back the original file. But I never modify things I don't understand. Anyway, I don't really know if my problem is software or hardware. I even changed my two PICs, maybe a factory default...but nothing.
I really start to become crazy... |
|
|
PCM programmer
Joined: 06 Sep 2003
Posts: 21708
|
|
| Posted: Thu Feb 20, 2014 12:28 am |
|
|
I was able to make my two board CAN bus test program work. I only
have one 18F46K80, so I used that on Board #2. I used an 18F2580
on Board #1. I didn't have two 8 MHz crystals so I used two 20 MHz
crystals. I can type into TeraTerm and see the typing OK.
I have posted a link to a photo of my test setup at the bottom. I am using
jumper wires as the "can bus". But I have MCP2551's and 120 ohm
resistors at each end. Note that I have a black ground jumper between
the two boards. This article says the CAN Bus needs one:
http://www.edn.com/electronics-blogs/dev-monkey-blog/4408712/Does-The-CAN-Bus-Need-a-Common-Ground-
I edited the can_init() routine in can-18F4580.c to set the correct TRISC,
the same as you did. That's the only change I made to that file. I left
this line unchanged:
| Code: | RXB0CON.rxm=CAN_RX_VALID;
|
One problem in your early code was that you didn't specify a fuse for
your 8 MHz crystal. So the compiler used the INTRC_HP fuse by default.
You were not running off the crystal but rather the internal oscillator.
Possibly this was the source of your problem (too many errors).
But you fixed that problem by using the HSM fuse in your later code.
Here is the program for Board #2 which has the 18F46K80:
| Code: |
#include <18F46K80.h>
#fuses HSH, NOPROTECT, PUT, BROWNOUT, NOWDT, NOPLLEN
#fuses CANC // *** Baklou is using CANC
#use delay(clock=20000000)
#include <can-18F4580.c> // Use correct driver
#define BOARD1_ID 24
#define BOARD2_ID 25
// Uncomment this line to compile code for Board #1.
// Comment it out to compile for Board #2.
//#define BOARD1 1
//======================================
void main()
{
struct rx_stat rxstat;
int32 rx_id;
int32 tx_id;
int8 rx_len;
int8 buffer[8];
can_init();
#ifdef BOARD1 // For Board #1
while(1)
{
buffer[0] = getc(); // Wait for a character
// Transmit it to board #2.
can_putd(BOARD2_ID, buffer, 1, 1, 1, 0);
buffer[0] = 0; // Clear the buffer byte
// Wait for the char to be echoed back.
while(!can_kbhit());
if(can_getd(rx_id, buffer, rx_len, rxstat))
{
if(rx_id == BOARD1_ID) // Is it for this board ?
{
putc(buffer[0]); // If so, display the char
}
}
}
#else // For Board #2
while(1)
{
if(can_kbhit()) // Message available ?
{
// If so, get the message.
if(can_getd(rx_id, buffer, rx_len, rxstat))
{
if(rx_id == BOARD2_ID) // Is it for this board ?
{
// If so, echo back the character.
can_putd(BOARD1_ID, buffer, 1, 1, 1, 0);
}
}
}
}
#endif
}
|
This is the Board #1 code:
| Code: |
#include <18F2580.h>
#fuses HS, NOPROTECT, PUT, BROWNOUT, NOWDT, NOLVP
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
#include <can-18F4580.c> // Use correct driver
#define BOARD1_ID 24
#define BOARD2_ID 25
// Uncomment this line to compile code for Board #1.
// Comment it out to compile for Board #2.
#define BOARD1 1
//======================================
void main()
{
struct rx_stat rxstat;
int32 rx_id;
int32 tx_id;
int8 rx_len;
int8 buffer[8];
can_init();
#ifdef BOARD1 // For Board #1
while(1)
{
buffer[0] = getc(); // Wait for a character
// Transmit it to board #2.
can_putd(BOARD2_ID, buffer, 1, 1, 1, 0);
buffer[0] = 0; // Clear the buffer byte
// Wait for the char to be echoed back.
while(!can_kbhit());
if(can_getd(rx_id, buffer, rx_len, rxstat))
{
if(rx_id == BOARD1_ID) // Is it for this board ?
{
putc(buffer[0]); // If so, display the char
}
}
}
#else // For Board #2
while(1)
{
if(can_kbhit()) // Message available ?
{
// If so, get the message.
if(can_getd(rx_id, buffer, rx_len, rxstat))
{
if(rx_id == BOARD2_ID) // Is it for this board ?
{
// If so, echo back the character.
can_putd(BOARD1_ID, buffer, 1, 1, 1, 0);
}
}
}
}
#endif
}
|
The photo in the link below shows the test setup. The green and yellow
jumper wires are needed because my MCP2551 is hardwired to the CAN
bus pins on PortB. To test the PortC pins (which you are using), I
jumpered them over.
http://s27.postimg.org/itynzzckj/Two_CAN_bus_boards.jpg |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ 
Search
Register
Profile 
Log in to check your private messages 
Log in
