Bolek
Tue Mar 02 04:23:11 CST 2004
Perhaps I could. I don't know much about parallel port and DMA or DMA at
all. Can you recommend me some articles on how to use it? Thanks.
Alex wrote:
> Can't you use DMA to output to the paralel port?
>
> or
>
> If it is experimental, you can do it one of this ways:
> Make the application for DOS, reprogram the system timer, write the
> apropriate INT hook. This should provide guaranteed timing.
> Hook the system timer interupt under windows(posible, not recomended, bad in
> a production application, everyone here will flame you for doing it).
> Use a realtime thread, write your own Sleep function based on the cpu time
> stamp counter and use it in a "..Sleep(something);DoJob();.." loop.(this
> will eat 100% of the CPU time).
>
>
>
> "Maxim S. Shatskih" <maxim@storagecraft.com> wrote in message
> news:eChOiMl$DHA.2576@tk2msftngp13.phx.gbl...
>
>> Nothing on USB can make a million of interrupts per second.
>>
>>--
>>Maxim Shatskih, Windows DDK MVP
>>StorageCraft Corporation
>>maxim@storagecraft.com
>>
http://www.storagecraft.com
>>
>>
>>"Pavel A." <pavel_a@geeklife.com> wrote in message
>>news:eayQHqI$DHA.4072@tk2msftngp13.phx.gbl...
>>
>>>There are several 8051 kits with USB interface like Cypress, or RS232,
>>>They are quite easy (*) to program and may do what the OP wants.
>>>
>>>--PA
>>>
>>>
>>>"Don Burn" <burn@stopspam.acm.org> wrote in message
>>
>>news:103rsi4qre55e9f@corp.supernews.com...
>>
>>>>No, you cannot get this level of performance. In theory you have a
>
> 10ms
>
>>>>timer, with the ability to boost that to a 1ms timer, but then things
>
> like
>
>>>>interrupt from other devices kick in. A customer of mine measured the
>>>>accuracy of the 1ms timer on their system and found it to anywhere
>
> from 1
>
>>to
>>
>>>>2.7 ms!
>>>>
>>>>--
>>>>Don Burn (MVP, Windows DDK)
>>>>Windows 2k/XP/2k3 Filesystem and Driver Consulting
>>>>Remove StopSpam from the email to reply
>>>>
>>>>"Bolek" <kraljaprvni@seznam.cz> wrote in message
>>>>news:ABF095B0-AF11-4A13-A934-616EF13E3EEA@microsoft.com...
>>>>
>>>>>Hello,
>>>>>
>>>>>I would like to write an application that would periodically write
>
> bytes
>
>>>>to the parallel port with frequency ranging from several Hz to 1MHz. I
>>>>thought I could use the hadrware timer to genearte interrupt every
>
> time and
>
>>>>write a device driver to handle it. However, my first question is: Is
>
> it
>
>>>>possible to accomplish it? I mean, is it possible to get such a high
>>>>frequency reliable under Windows? will not my interrupts be delayed by
>
> task
>
>>>>switching, other interrupts etc. Is it possible to disable task
>
> switching
>
>>>>etc for a short time? Or would it be realiable at least in the case
>
> that no
>
>>>>other applications run?
>>>>
>>>>>Thank you very much
>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>
>