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ukaza
Joined: 10 Feb 2004
Posts: 1
Location: TURKEY
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| serial communication channels of 16F84A |
 Posted: Sat Mar 06, 2004 3:47 am |
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I have a problem with 16F84A. I am using one pin of 16F84A as receiving pin and I am satisfied with good results, that is no problem about the serial communication.
However I want to use three pins of the 16F84A as receiving pin.Because I have three infrared receivers.
How can I do this?
Can you suggest a software solution?
If impossible with software what should I do?
Thank you for your help....... |
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Ttelmah
Guest
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| Re: serial communication channels of 16F84A |
| Posted: Sat Mar 06, 2004 4:27 am |
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| ukaza wrote: | I have a problem with 16F84A. I am using one pin of 16F84A as receiving pin and I am satisfied with good results, that is no problem about the serial communication.
However I want to use three pins of the 16F84A as receiving pin.Because I have three infrared receivers.
How can I do this?
Can you suggest a software solution?
If impossible with software what should I do?
Thank you for your help....... |
So long as you can guarantee that only one receiver will send data at a time, what you want can be done.
Put the three inputs onto the high PORTB pins (RB4:7 - use just three of these). In the main code, read PORTB, and enable the 'interrupt on change' feature on these pins. Then when the interrupt takes place, read PORTB, and check which of the pins has dropped. The code will be something like:
| Code: |
int1 RX_DATA=false;
#INT_RB
void port_has_changed(void) {
int8 ipval;
ipval=INPUT_B();
disable_interrupts(INT_RB);
RX_DATA=true;
if ((ipval & 0x10)==0) {
#USE_RS232(baud=1200,parity=N,rcv=PIN_B4);
return;
}
if ((ipval & 0x20)==0) {
#USE_RS232(baud=1200,parity=N,rcv=PIN_B5);
return;
}
#USE_RS232(baud=1200,parity=N,rcv=PIN_B6);
}
//Note that the code will only pick up the 'first' bit that has dropped
//and that you must ensure B7, does not change.
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In the 'main', you will need to read port B, and then enable the RB interrupt. Then sit waiting for 'RX_DATA' to go true. When it does, use:
| Code: |
char=getc(); //This will read the character from the selected input bit
RX_DATA=false;
enable_interrupts(INT_RB);
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Obviously, you could also use the 'stream' ability, and set the stream in the interrupt. You may also want to just set a number so you know which pin has received the data.
Where you will get problems, is if more than one receiver sends data at the same time...
Best Wishes |
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