HID host USB for getting barcode from a scanner.

Hi

I use HID host as USB profile for getting barcode from scanner (ES4650 scanner).

I use STM32F746.

Most of the time I get the right barcode, but sometimes it misses a character .

I tried giving its interrupt the top priority, but it didn't solve the problem.

When trying the same scanner on a PC with a PC software, I always get the right barcode.

What can be the problem ?

Thanks

Ofer

Super User

Hi,

To check, whether there is a problem with the D-cache (if you have it on) , just switch off (or not enable) the D-cache.

"If you feel a post has answered your question, please click ""Accept as Solution""."

Visitor II

Here are some barcode reading solutions. Some may become helpful to you.

If you ever try to make an ESPhome based barcode scanner, you can try this:

OferAuthor

Associate III

Thank for your replies.

I solved this bug.

I uncommented all the 6-7 in my main loop and found that one of them caused the bug.

It was a function that read data from sensors (21 same temperature DS18S20 sensors).

Instead of reading all the 21 sensors every iteration I changed to read only one sensor on each iteration.

Those sensors and the USB are connected to the same 5V power supply.

The sensors which have 1-wire interface need a large pull-up so they probably affect somehow on the USB.

Thanks anyway.

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