Simple Application

Hello,

I am trying to write a simple application that will look at a hardware
address lets say &HA400 or &H378 approximately 1000 times per second.

Every 100th time though I need to write out the value to the registry
(any place will work).

Is a device driver appropriate for this kind of application? If not,
can someone point me to the right newsgroup? If so, does anyone have
any examples or port IO or registry writing?

Thanks In Advance,
Terry

Robert
Tue Apr 26 01:50:28 CDT 2005

TerryW <prog wrote:
> Hello,
>
> I am trying to write a simple application that will look at a hardware
> address lets say &HA400 or &H378 approximately 1000 times per second.

How precise should that be? Windows is not very accurate in the
msec area.

TerryW
Tue Apr 26 09:27:19 CDT 2005

Not very precise at all. I don't need RTOS

On Tue, 26 Apr 2005 08:50:28 +0200, Robert Marquardt
<marquardt@codemercs.com> wrote:

>TerryW <prog wrote:
>> Hello,
>>
>> I am trying to write a simple application that will look at a hardware
>> address lets say &HA400 or &H378 approximately 1000 times per second.
>
>How precise should that be? Windows is not very accurate in the
>msec area.

David
Tue Apr 26 13:04:29 CDT 2005

How could we know? The information provided is insufficient to determine
requirements. "Not very precise" is like saying the targeting for a .223
bullet or atomic bomb is similar.

Can all 1000 hardware accesses occur and then hope to get your driver back
in control sometime in the next second? What are minimum and maximum times
that the hardware must be accessed to provide useful data? How long does
each access take? How long does it take to clear the device's state? Since
0x378 is a parallel port address, IIRC, can it be used with interrupts
enabled? DMA?

Since you asked the question showing a Basic programmer's mindset, the first
answer stands a very good chance of being correct. Almost no one working
with hardware uses the &H notation. It is usually 0x for 'C/C++' or 0NNNNh
for assembly.

"TerryW @vbssys.com>" <prog<NOSPAM> wrote in message
news:dtjs61l9ore1g2d610c5q205ecsj5n2j5u@4ax.com...
> Not very precise at all. I don't need RTOS
>
> On Tue, 26 Apr 2005 08:50:28 +0200, Robert Marquardt
> <marquardt@codemercs.com> wrote:
>
>>TerryW <prog wrote:
>>> Hello,
>>>
>>> I am trying to write a simple application that will look at a hardware
>>> address lets say &HA400 or &H378 approximately 1000 times per second.
>>
>>How precise should that be? Windows is not very accurate in the
>>msec area.
>

Tim
Wed Apr 27 01:05:28 CDT 2005

TerryW <prog<NOSPAM>@vbssys.com> wrote:
>
>I am trying to write a simple application that will look at a hardware
>address lets say &HA400 or &H378 approximately 1000 times per second.
>
>Every 100th time though I need to write out the value to the registry
>(any place will work).

In that case, why not just read it 10 times per second? Context switching
is expensive.

>Is a device driver appropriate for this kind of application? If not,
>can someone point me to the right newsgroup? If so, does anyone have
>any examples or port IO or registry writing?

You will need SOME kind of driver, but not necessarily a custom one. There
are packges like giveio or dlportio that can allow a user-mode app to read
I/O ports.

What are you really trying to do?
--
- Tim Roberts, timr@probo.com
Providenza & Boekelheide, Inc

Gary
Sat Apr 30 16:57:23 CDT 2005

Maybe you don't need RTOS, but in Windows NT through XP/SP2 you absolutely
will need a kernel mode device driver to acces those ports.

--
Gary G. Little

"TerryW @vbssys.com>" <prog<NOSPAM> wrote in message
news:dtjs61l9ore1g2d610c5q205ecsj5n2j5u@4ax.com...
> Not very precise at all. I don't need RTOS
>
> On Tue, 26 Apr 2005 08:50:28 +0200, Robert Marquardt
> <marquardt@codemercs.com> wrote:
>
>>TerryW <prog wrote:
>>> Hello,
>>>
>>> I am trying to write a simple application that will look at a hardware
>>> address lets say &HA400 or &H378 approximately 1000 times per second.
>>
>>How precise should that be? Windows is not very accurate in the
>>msec area.
>