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Baud rate out with HiTec Compiler
Posted: Thu Nov 10, 2011 5:00 pm
by medelec35
I have been playing with Hitec and bit banging RS232. With osc at 8MHz
The baud rates are way out.
e.g in rs232.c
for
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#define %m_SW_BAUD %r - 20 //Under 10MHz
Baud = 497
For
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#define %m_SW_BAUD %r - 255 //Under 10MHz
Baud = 1219
Since 255 is maximum variable can be, what would I need to adjust to get baud at a higher rate please?
Martin
Re: Baud rate out with HiTec Compiler
Posted: Thu Nov 10, 2011 5:36 pm
by medelec35
I’m guessing I am looking to change %r which currently set to 416?
Unfortunately I can't determine where the 416 is assigned.
Re: Baud rate out with HiTec Compiler
Posted: Thu Nov 10, 2011 6:32 pm
by medelec35
I’m assuming %r is calculated from required baud rate.
To give an idea on value of %r. I have got the baud rate of 2400 spot on by changing #define line to
This would imply HiTec bitbang RS232 is miles off from BoostC.
Therefore I would guess there would have to a separate defines for Boostc and HiTec .
Martin
Re: Baud rate out with HiTec Compiler
Posted: Fri Nov 11, 2011 11:44 am
by Benj
Hi Martin,
I will make a note to have a good look into this for hitech and boostc for the v5 CAL code as it allows any component that uses a UART to tap into the hardware/software UART functionality. Hopefully we can get something more reliable across the board.
Re: Baud rate out with HiTec Compiler
Posted: Tue Nov 15, 2011 4:49 pm
by medelec35
Thanks for reply Ben
I have done some further tests on just using boostC.
I have used two frequencies and two different baud rates
Here are results I had to adjust RS232 component to, in order for RS232 baud rates to be spot on.
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Freq Baud Value
4MHz 2400 %r - 80 Therefore if default is %r - 58, then %r should be 434 etc
4MHz 4800 %r - 54
8MHz 2400 %r - 40
8MHz 4800 %r - 27
Would you mind letting me know a way I can set it up so %r can be reclulated for the different baud rates and different frequencies please and not just different baud rates.
Thanks
Martin