Re: [Flashforth-devel] strange answer from UART

[Peter J. <pe...@me...>]

Can you simply turn on the PLL (OSC = HSPLL) to get a 16MHz sys-clock 
frequency?  I've quite happily run a PIC18F2520 at 38400 baud with a 
4MHz crystal and the PLL active.
Peter J.


On 17/03/14 18:33, Herman Attila wrote:
> Hi Thomas,
>
> Maybe your problem comes from low Osc-frequency/baudrate ratio. Using 4MHz osc freq. the controller generates the 38400kbs with 10% error. Try to use higher osc freq. or lower baudrate. Otherwise I recommend you to use 18F26K22 or other xxk22 controllers. They have well configurable internal oscillator and have several further excellent features.
>
> BR
> Attila
>
> ----- Eredeti üzenet -----
> Feladó: Thomas Buschhardt <bus...@gm...>
> Dátum: Hétfő, Március 17, 2014 8:32
> Tárgy: [Flashforth-devel] strange answer from UART
> Címzett: Fla...@li...
>
>
>> Dear Mikael and mailing listeners,
>>
>> I desperated, I got some strange signs back from the PIC. In my
>> despair - I
>> installed even MS Windows, to see whether my usb-2-serial adapter is broken
>> - but the program "Hyperterminal" shows the same results.
>>
>> Here is my configuration:
>>
>> PIC18F2620
>> 4 MHz Oscillator Link to
>> Oszillator<>
>> MAX232
>> FD-USB2Serial-Adapter
>>
>> The programing - process runs well with my PICKIT2. When the PIC gets
>> power
>> its send the same strange signs, and if I blind input "1 2 3" (to the
>> stack) in the terminal, I got a answer - that could be the right one.
>> --snip--
>> 38400 -  8 - N - 1
>> ¦¬¡³¸¦¯²´¨ •Ž° °©£±˜ Š Š‘
>> ¦¬¡³¸¦¯²´¨ •Ž° °©£±˜ Š Š‘
>> ¦¬¡³¨¦¯²´¸ •Ž° °©£‘¸ Š Š‘
>> ± ² ³ ± ² ³ Ÿ Š
>> --snip--
>> Here I restart 3 times the PIC and input "1 2 3" and get back "± ² ³ Ÿ
>> Š".
>>
>> I changed the baudrate, oszillator frequency, the oscillator selection
>> bits
>> - without success.
>> I hope I do some configuration mistakes, so please help me.
>>
>> The schematics for my hw-configuration, the (binary) log-file of the
>> terminal and my changed configurations-files you can find here as zip
>> file.
>>
>>
>>
>>
>> If you need more informations, please drop me a mail.
>>
>> Greetings Thomas
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