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John Morley
Joined: 09 Aug 2004
Posts: 97
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| Problem with Int_RDA |
 Posted: Fri Dec 16, 2005 6:34 pm |
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Hi all,
I'm experiencing a strange problem getting the serial interrupt to work on a 16F628 using compiler version 3.162. I know my hardware is OK because I can do this:
| Code: |
Main()
{
char c;
while(1)
{
c=fgetc(Console);
fputc(c,Console);
} // while
}
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All the characters I type on Hyperterminal get echoed right back correctly. However, when I try to use an interrupt to do basically the same thing it doesn't work 
Here is a small test program:
| Code: |
//-----< Include Files, setup fuses >-----
#include <16f628.h>
#fuses HS, NOWDT, NOPROTECT, NOLVP
//-----< Compiler use statements >-----
// Tell compiler clock speed is 20.00 MHZ Crystal
#use delay(clock=20000000)
//-----< General Program Defines >-----
#define Console_Out PIN_A4 // Software RS232 Output to Console Terminal (requires MAX232)
#define Console_In PIN_B1 // Hardware RS232 Input from Console Terminal (requires MAX232)
//-----< Serial Port Definitions >-----
#use rs232(baud=9600, xmit=Console_Out, rcv=Console_In, ERRORS, STREAM=Console)
//-----< Get a RS232 command packet >-----
// Note: This routine is interrupt driven. RS232 input takes priority
// over every other operation in the system.
#int_rda // Interrupt driven RS232 routine
void rs232_isr(void)
{
char temp; // local data storage
temp = fgetc(Console); // get rx data
fputc(temp, Console);
}
Main()
{
enable_interrupts(INT_RDA);
enable_interrupts(GLOBAL);
fprintf(Console,"\n\rHere at the start\n\r");
while(1)
{
} // while
} // end Main
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When I run this code I never see any characters echoed back. I can see the data arrive just fine at Pin B1 on a scope, but the interrupt doesn't fire!
Any thoughts?
Thanks!
John
_________________
John Morley |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Dec 16, 2005 6:54 pm |
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You can't split the hardware UART pins. It's either all hardware or
all software. If you make one pin of the hardware UART become a
software UART, then both pins will be a soft UART. This is a limitation
of the PIC hardware. INT_RDA only works with the hardware UART.
To get a hardware UART for the 16F628, you need to use these pins:
use rs232(baud=9600, xmit=PIN_B2, rcv=PIN_B1, ERRORS, STREAM=Console) |
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John Morley
Joined: 09 Aug 2004
Posts: 97
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| Posted: Fri Dec 16, 2005 9:19 pm |
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PCM,
Thanks for catching that. I'm not sure if it solves my problem, however, as I was never using a serial out to begin with, but added it when I has trouble with the serial interrupt. I'll make the serial output a separate stream for the purposes of my testing and report back.
Thanks Again!
John
_________________
John Morley |
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John Morley
Joined: 09 Aug 2004
Posts: 97
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| Posted: Mon Dec 19, 2005 8:50 am |
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Hi All,
I made a change to my test program this morning to separate the serial input and output onto two distinct streams, but I still can't get the serial interrupt to work at all. Again, compiler is version 3.162.
| Code: |
//-----< Include Files, setup fuses >-----
#include <16f628.h>
#fuses HS, NOWDT, NOPROTECT, NOLVP
//-----< Compiler use statements >-----
// Tell compiler clock speed is 20.00 MHZ Crystal
#use delay(clock=20000000)
//-----< General Program Defines >-----
#define Console_Out PIN_A4 // Software RS232 Output to Console Terminal (requires MAX232)
#define Console_In PIN_B1 // Hardware RS232 Input from Console Terminal (requires MAX232)
#define Test_Output PIN_A1 //Pin #18
//-----< Serial Port Definitions >-----
#use rs232(baud=9600, rcv=Console_In, ERRORS, STREAM=Console1)
#use rs232(baud=9600, xmit=Console_Out, STREAM=Console2)
//-----< Get a RS232 command packet >-----
// Note: This routine is interrupt driven. RS232 input takes priority
// over every other operation in the system.
#int_rda // Interrupt driven RS232 routine
void rs232_isr(void)
{
char temp; // local data storage
temp = fgetc(Console1); // get rx data
fputc(temp, Console2);
}
Main()
{
enable_interrupts(INT_RDA);
enable_interrupts(GLOBAL);
fprintf(Console2,"\n\rHere at the start\n\r");
while(1)
{
} // while
} // end Main
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Again, I know my hardware is OK because I can put the fgetc and the fputc in Main, and all characters are echoed just fine. But for some reason it won't work using the interrupt
Thanks!
John
_________________
John Morley |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Dec 19, 2005 2:08 pm |
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Let me be more explicit.
You cannot define half of a hardware serial port with a #use rs232()
statement. If you try to do so, the compiler generates a software UART.
i.e., the following statement in your program will make a soft UART:
| Code: | #use rs232(baud=9600, rcv=Console_In, ERRORS, STREAM=Console1)
or more plainly:
#use rs232(baud=9600, rcv=PIN_B1) |
To get a hardware UART, you must put both hardware UART pins
in the #use rs232() statement. Example for 16F628:
| Code: | #use rs232(baud=9600, xmit=PIN_B2, rcv=PIN_B1, ERRORS)
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Also, the ERRORS directive only works with the hardware UART.
If you include it with a soft UART, the compiler will ignore it. |
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John Morley
Joined: 09 Aug 2004
Posts: 97
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| Posted: Mon Dec 19, 2005 8:59 pm |
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PCM,
Ugh, I've got it now  ! Thanks for taking another swing at this one, I really appreciate it! And, yes, it's working!!
Thanks!
John
_________________
John Morley |
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