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fuzzy
Joined: 26 Feb 2005
Posts: 64
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| MULTI_MASTER declaration in #USE RS232 |
 Posted: Fri Jun 30, 2006 4:30 am |
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In my code I use this declaration in PIC16F876:
#use rs232(baud=9600 ,xmit=PIN_C6,rcv=PIN_C7,enable=PIN_C5,parity=e)
if i try to use MULTI_MASTER optinn
#use rs232(baud=9600 ,xmit=PIN_C6,rcv=PIN_C7,enable=PIN_C5,parity=e,MULTI_MASTER)
i've problems and i cant compile my code, instead it works fine.
Problems seem to concern ROM . as compilers goes out of ROM.
how can i solve this problem? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Jun 30, 2006 4:56 pm |
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| Quote: |
If i try to use MULTI_MASTER option, i've problems and i cant compile my
code. Problems seem to concern ROM, as compiler goes out of ROM.
#use rs232(baud=9600 ,xmit=PIN_C6,rcv=PIN_C7,enable=PIN_C5,parity=e,MULTI_MASTER)
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I don't get that error. I do get the following error message from
the compiler if I try to compile your #use rs232 line.
| Quote: | | Error: USE parameter value is out of range. H/W USART cannot multi-master |
The CCS manual says you can't use the hardware UART (on pins C6 and
C7) for Multi-Master mode:
| Quote: | MULTI_MASTER -- Uses the RETURN pin to determine if another master
on the bus is transmitting at the same time. If a collision is detected bit 6
is set in RS232_ERRORS and all future PUTC's are ignored until bit 6 is
cleared. The signal is checked at the start and end of a bit time.
May not be used with the UART. |
You have to use a soft UART with Multi-Master mode. You can use pins
that are not used by the hardware UART, such as B1 and B0. Example:
| Code: | | #use rs232(baud=9600 ,xmit=PIN_B1,rcv=PIN_B0,enable=PIN_C5,parity=e,MULTI_MASTER) |
Or, if you want to use pins C6 and C7, you can add the FORCE_SW
parameter as shown below, and the compiler will create a soft UART
on those pins. Example:
| Code: | | #use rs232(baud=9600 ,xmit=PIN_C6,rcv=PIN_C7,enable=PIN_C5,parity=e,MULTI_MASTER,FORCE_SW) |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Sat Jul 01, 2006 8:07 am |
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| Quote: |
i've problems and i cant compile my code, instead it works fine.
Problems seem to concern ROM . as compilers goes out of ROM.
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You did not post the preprocessor definitions used in the header in your code.
Are you aware of #device *=16 pointer qualifier for 16F series ?
Did you try to reduce the size of some of your bigger functions for a most efficient
allocation in memory blocks ?
| Quote: |
In my code I use this declaration in PIC16F876:
#use rs232(baud=9600 ,xmit=PIN_C6,rcv=PIN_C7,enable=PIN_C5,parity=e)
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What compiler version are you using ? I had problems regarding the "enable pin"
handler with some of the last versions.
Humberto |
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