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robin171
Joined: 12 Sep 2008
Posts: 4
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| hardware uart does not receive all the characters |
 Posted: Fri Sep 26, 2008 9:02 am |
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Hi,
I have a problem with the hardware uart of the PIC16F877A. The UART is connected to a powerline modem (ST7538).
The problem is that I only receive the last characters of the string. I send a string of about 20 characters, the first 10 are not received. I checked the RX pin of the PIC with a scope. The characters I use the #INT_rda interrupt to receive the characters.
here is my interrupt routine:
| Code: | #int_RDA
void RDA_isr()
{
byte data = 0;
if(kbhit(COM1))
{
data = getc(COM1);
if(data)
{
fputc(data,COM2);
write_buffer((buf_t *)&rcv_buffer,data);
}
}
} |
COM2 is a software UART. write_buffer is a function which puts the data in my buffer and checks for control characters. Here is the function:
| Code: | boolean write_buffer(buf_t *buffer, byte data)
{
if(!buffer->full)
{
buffer->data[buffer->wr_idx] = data;
switch(data)
{
case '$':
buffer->rcvd_dollar = true;
buffer->dollar_position = buffer->wr_idx;
break;
case '*':
buffer->rcvd_star = true;
buffer->star_position = buffer->wr_idx;
break;
case '\n':
buffer->rcvd_nl = true;
buffer->nl_position = buffer->wr_idx;
break;
default:
}
buffer->wr_idx++;
if(buffer->wr_idx >= RCV_BUF_SIZE)
{
buffer->full = true;
}
return true;
} else {
return false;
}
} |
I use the following statement to configure the UART:
| Code: | | #use rs232(baud=600,UART1,stream=COM1,errors) |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Sep 26, 2008 11:26 am |
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Do some tests. Comment out the fputc() for the software UART, inside
the INT_RDA isr. Dump the buffer after you've sent a string.
Did you get it all, this time ? If so, the problem is in the fputc() inside
the isr. What's the baud rate for the soft UART ? You didn't post the
#use rs232() statement for that one. |
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