win7 & jdm programmer

Problems or tips related to the use of WxPic

Re: win7 & jdm programmer

Postby admin » 31, 2010 Aug Tue 7:20 pm

Hi,

I am happy that you got it working.

The new error about delay means that the PC high frequency timer does not measure correctly the time because it has not a stable frequency. Its frequency seems to vary from 2.5277 to 3.9458 MHz. This makes difficult for WxPic to measure precisely the small delays of few µs.

Have you some utility that modifies the system clock speed? If it is the case you should disable it when you are using WxPic. If this is a native capacity of Seven, there may be some parameter to disable it. Else I don't know why Windows would return different frequencies depending on the moment.

Philippe
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Re: win7 & jdm programmer

Postby double » 01, 2010 Sep Wed 9:24 am

i am happy, too :)
thanks for your support and the nice work of the programmer software.

do you mean, pc overclocking? yes i do, i deactivate this but the frequency is not realy stable.
the programmer could not initialize each time, but with remove the pic the wx pic programm detect the programmer better and i can work with it.

new additional serial port parameter in seven i have not found, looks like xp
do you think the problem can be the long serial cable?
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Re: win7 & jdm programmer

Postby admin » 01, 2010 Sep Wed 8:24 pm

Hi,

The long serial cable won't help for sure. But you can compensate by increasing of few µs the extra clock and data delays. This will slow the programming cycle but it should be more reliable.

The overclocking, if constant, is not a problem. Anyway normally no legal operation should affect the frequency of the timer:
MSDN wrote:QueryPerformanceFrequency
Retrieves the frequency of the high-resolution performance counter, if one exists. The frequency cannot change while the system is running.


Though it may exist some buggy BIOS around performance counter:
MSDN wrote:On a multiprocessor computer, it should not matter which processor is called. However, you can get different results on different processors due to bugs in the basic input/output system (BIOS) or the hardware abstraction layer (HAL).

But I find this strange because the High Res timer is not a standard device managed by the BIOS. I believe that the PC requires a specific driver to recognize the timer. Have you the right drivers for your mother board (no yellow question mark in the hardware device manager)?

Philippe
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