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microchip C18 c compiler software RS232

 
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Sigma
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microchip C18 c compiler software RS232
PostPosted: Fri Apr 30, 2004 2:45 am     Reply with quote
Hi, Friends,
I am now using microchip C18 controller and pic18f452.
This compiler does not have the #use rs232 directives, therefore i may need to write the software RS-232 communication protocol myself.
And my hardware uart is already in use by another communication channel.
Did any of you implement this before? Or do you have any sample codes?
Thanks.
Sigma
Sigma
Guest
PostPosted: Fri Apr 30, 2004 3:04 am     Reply with quote
By the way, i did see some posts using interrupt to achieve this. But could not see anyone using polling. Why? I like polling.
Sigma
Haplo



Joined: 06 Sep 2003
Posts: 659
Location: Sydney, Australia

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PostPosted: Fri Apr 30, 2004 3:23 am     Reply with quote
You can't sample exactly in the middle of the bits if you use polling, because you will need to generate exact delays using loops/delay_us() which is not practical.
This post may be a good starting point:
http://www.ccsinfo.com/forum/viewtopic.php?p=24470&highlight=#24470
dyeatman



Joined: 06 Sep 2003
Posts: 1912
Location: Norman, OK

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C18 Resource
PostPosted: Fri Apr 30, 2004 6:25 am     Reply with quote
This site is a very good resource for code that should work for the C18 compiler (including the software RS232) and you would likely get more info there. C18 folks dont hang around here much...

http://www.microchipc.com/

You shoudl also try the microchip C18 programmers forum here:

http://forum.microchip.com/tt.asp?forumid=-2
Sigma
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PostPosted: Mon May 03, 2004 7:30 pm     Reply with quote
Thx, all.
Sigma



Joined: 03 May 2004
Posts: 48
Location: Sg

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PostPosted: Sun May 09, 2004 9:33 pm     Reply with quote
Hi, all,
I am now trying to convert the assembly code of AN555 to PIC C code, where i encountered a problem.
There is one section in the rs232.h i don't quite understand,
Code:
LOAD_RTCC   MACRO   Mode, K, Prescale

    if(UsePrescale == 0 && Mode == 0)
   movlw   -K + _Cycle_Offset1
    else
   movlw   -K + (_Cycle_Offset1 >> (Prescale+1))  ; Re Load RTCC init value + INT Latency Offset
    endif
   movwf   TMR0      ; Note that Prescaler is cleared when RTCC is written

      ENDM

The assembler does not understand LOAD_RTCC MACRO Mode, K,Prescale, and so do i. What does it mean? How could i use it under CCS compiler?
Thanks.
Sigma
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