[vox-tech] Must a 300 microsecond delay keep the CPU busy?

[John Wojnaroski]

Most likely you will have to write your own function/routine/module.  
Good news there are many tutorials and examples with source code on the 
web.  Try googling on "interfacing parallel port" for starters

Regards
John W.

Chris Jenks wrote:

>
> On Tue, 4 Apr 2006, John Wojnaroski wrote:
>
>> Not knowing the details of your board, it is a little tough to 
>> propose a better solution, but here goes.
>>
>> Since your using the parallel port, you should consider an interrupt 
>> based driver, have the board provide the interrupt signal when the 
>> A/D conversion is completed. Most A/D chips provide a sense line that 
>> indicates when the converion is completed and the data can be read. 
>> that way you don't have to "wait" for the board.
>> Connect the sense line to the interrupt pin on the parallel port.
>>
>> Then create a tasklet that is called by the driver to move the data 
>> from kernel space to user space.
>>
>> This is a bit more complex than a simple polling scheme, but far more 
>> elegant and reliable and totally independent of CPU speed or 
>> processor performance. Odds are you won't even notice the short time 
>> the CPU is servicing the interrupt.
>>
>> Regards
>> John W
>
>
>   Dear John,
>
>   That sounds like the best solution. The A/D IC does have an End Of 
> Conversion pic that I can connect to any of the parallel port inputs. 
> I'm relatively new to C. Do you know of a function I can cell that 
> would wait for an interrupt from the parallel port, or is it necessary 
> for me to write one?
>
>   Yours,
>
>     Chris
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