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sraiderk
Joined: 09 Feb 2005
Posts: 48
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| Could you help me about can_init |
 Posted: Mon Feb 21, 2005 10:19 am |
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Hi, everybody
I am trying to communicate two 16f877 using 2510 with help of can bus driven by mcp2551. I use the driver can-mcp2510.c. But, My pics don't make the can_init(); operation. This line never finished by pics. What can be wrong.
lcd_init();
can_init();
printf(lcd_putc,"I AM MASTER");
I never see the I AM MASTER on lcd but if I write like that
lcd_init();
printf(lcd_putc,"I AM MASTER");
can_init();
I see the I AM MASTER on lcd.
16F877 and MCP2510 There is a 4 connection pins. I never use the int pin of the mcp2510. sck,so,si,cs. I changed the CS pin from the file can-mcp2510.c . The others remain constant. Xtal:4mhz used for mcp2510.
help me please! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Feb 21, 2005 10:36 am |
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You don't have to keep posting over and over again.
We saw your post the first time.
If a program stops when it talks to a hardware driver,
the reason is probably that it's waiting in a polling loop.
It's reading the device and waiting for a bit to be in
a certain state (high or low) and the bit never goes
into that proper state. So the program stays in that
loop forever.
So, you should look at the code in the can_init() function.
Look for places where it reads the MCP2510. Also, look
in all sub-routines that are called by can_init().
When I do this, I find the following code in can_set_mode():
| Code: | do {
old_CANCTRL=mcp2510_read(CANCTRL);
} while (old_CANCTRL.reqop != mode); |
This may be where the problem is. One easy way to check
is to temporarily put some printf or putc statements before and
after that code. Something like this:
| Code: | putc('A');
do {
old_CANCTRL=mcp2510_read(CANCTRL);
} while (old_CANCTRL.reqop != mode);
putc('B'); |
Now run your program. If you see "AB" on the terminal window,
then it's executing that section OK. But if you only see "A",
then the program is stuck in that section.
You should do this. If it locks up in that section, then look closely
at your MCP2510 SPI bus signals. Do you have them connected
properly ? You said you moved the CS signal. What pin did you
put it on ? Is another device (such as the LCD) connected to
any of those SPI pins ? Did you put CS on pin A4, and then forget
to put a pull-up resistor on that pin ? Look for things like this. |
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sraiderk
Joined: 09 Feb 2005
Posts: 48
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| Posted: Tue Feb 22, 2005 3:55 am |
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| Thank you very much your help. I saw A then I made pull up correction on my circuit. It is fine. |
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