Letancy timer - FTDI

[milan87]

Hello All,

i use some device with FTDI chip, and latency timer should be reduce from 16ms to 3ms.

I created small VI that can do this, but there is a problem. In att.

For example i use one device and timer is set to 3ms.

Then I use another device, totally the same as first, but error occurred: -604.

Can someone advise what is happening here?

P.S. computer is not locked by the administrator.

Thanks

[GerdW]

Hi Milan,

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@milan87 wrote:

Can someone advise what is happening here?

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You're not allowed to access that registry key…

[milan87]

OK, thanks on fast feedback.

How i can access to that registry for one device and not on another?

Have you idea how to overcome this?

[rolfk · Accepted solution]

You need to change the permissions for that registry key in the registry editor (or the registry folder containing that key) to have write access for your user.

What might have happened is that the device was in the first situation for the first time enumerated under your current user account and the according permission was set, but the enumeration for the second device happened under different user credentials. These keys get created by the PnP device installation during the first time a device is detected based on the USB vendor and product ID and the reported serial number.