Re: [Amforth-devel] mega8 installation problem

[<r.g...@vi...>]

Hi Feusag,
thanks for fast response!
I changed init usart routine as You recomended, but I'm not shure that understand 
You right! 
Can You send complete routine to me?
thanx,
Robert

> 
> Od: "Feusag Mhor" <feu...@go...>
> Datum: 2007/09/05 sri PM 06:22:08 GMT+01:00
> Za: amf...@li...
> Naslov: Re: [Amforth-devel] mega8 installation problem
> 
> Hi,
> 
> I had the same problem and traced it to the baud rate calculation.
> 
> It turns out that there is a 7% error at 9600 baud with a 1MHz system clock
> (see table 60 in the datasheet) and this is out of spec for you PC UART to
> read.
> 
> I changed the baud rate on line 22 of template.asm to 4800 (0.2% error) and
> everything was OK.
> 
> I have also prototyped the following change to armforth/words/usart.asm to
> use the U2X double speed mechanism.
> With this change the error at 9600 baud is 0.2% with a 1MHz clock and works
> perfectly.
> 
> Index: usart.asm
> 
==================================================================
=
> --- usart.asm   (.../vendor/amforth/2.3/words/usart.asm)
> +++ usart.asm   (.../trunk/forth/amforth/words/usart.asm)
> @@ -81,7 +81,7 @@
>    .dw XT_D2SLASH
>    .dw XT_D2SLASH
>    .dw XT_D2SLASH
> -  .dw XT_D2SLASH
> +;   .dw XT_D2SLASH                             ; We are going for 2X, so
> remove one of these...
>    .dw XT_ROT
>    .dw XT_UMSLASHMOD
>    .dw XT_SWAP
> @@ -96,7 +96,14 @@
>    .dw XT_DOLITERAL
>    .dw BAUDRATE0_HIGH
>    .dw XT_CSTORE
> +
>    .dw XT_DOLITERAL
> +  .dw $02                                              ; U2X
> +  .dw XT_DOLITERAL
> +  .dw $2B                                              ; UCSRA
> +  .dw XT_CSTORE
> +
> +  .dw XT_DOLITERAL
>    .dw (1<<UMSEL01)|(3<<UCSZ00)
>    .dw XT_DOLITERAL
>    .dw USART0_C
> 
> 
> 
> I hope this helps.
> 
> Cheers
> 
> Feusag
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Splunk Inc.
> Still grepping through log files to find problems?  Stop.
> Now Search log events and configuration files using AJAX and a browser.
> Download your FREE copy of Splunk now >>  http://get.splunk.com/
> _______________________________________________
> Amforth-devel mailing list
> Amf...@li...
> https://lists.sourceforge.net/lists/listinfo/amforth-devel
> 
>