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pilar
Joined: 30 Jan 2008
Posts: 197
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| Is possible to have several #INT_RDA of different STREAM? |
 Posted: Wed Sep 30, 2009 8:32 am |
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Hi, I am using the PIC18F452 and I need to capture the strings of three peripherals, they have different speeds (KB) and number of characters, I am taking this example like reference, where is implemented 2 UARTS by software, I doubt it, I can get different interruption (#INT_RDA)?
| Code: | #USE RS232(BAUD=9600, XMIT=PIN_B0, RCV=PIN_B1, STREAM=COM_A)
#USE RS232(BAUD=9600, XMIT=PIN_B2, RCV=PIN_B3, STREAM=COM_B)
#INT_RDA (COM_A)
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.
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#INT_RDA (COM_B)
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.
main() {
char c;
fprintf(COM_A,"Online\n\r");
fprintf(COM_B,"Online\n\r");
while(TRUE) {
c = fgetc(COM_A);
fputc(c, COM_A); fputc(c, COM_B);
}
} |
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Ttelmah
Guest
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| Posted: Wed Sep 30, 2009 8:45 am |
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INT_RDA, is a _hardware_ feature, for the hardware UART.
If you choose a chip that has multiple hardware UARTs, then you get INT_RDA, and INT_RDA2. On a chip like yours, with only one hardware UART, you can only have one INT_RDA.
For the software UART, you don't get an INT_RDA (INT_RDA, says there is a character waiting in the hardware buffer - software UART, no hardware buffer....).
You can use the interrupt input line(s), and program an interrupt on this/these falling, to say that the 'start' bit has arrived on a particular serial line, (search here many examples posted in the past) _but_ while receiving this, you _will_ miss anything happening on other lines.
The alternative is to use external hardware UARTs, with buffers, and use these to interrupt the main chip.
Best Wishes |
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