Load Bitmap return message missing a byte

GTT TFT Support

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Load Bitmap return message missing a byte

Post by grnbriar » Fri Mar 27, 2015 8:46 pm

I have had an issue for a while, where my system would lock up on start on, sometimes. This week it became all the time.
If I reset my system, it works fine, but if I power it off and back on it hangs.

Found the culprit tonight -
On power up I have 4 commands in an on board startup file:
Load Bitmap, Display Bitmap, Load Font and Set Font

it turns out the Load Bitmap command always sends me - 252 95 1 254,
which, being a 252 command I process as message length 510. The other 4 returns are always
252 97 0 1 254
252 40 0 1 254
252 49 0 1 254
to show success.
My message buffer that I use to pull bytes out of the interrupt circular buffer is only 16 bytes, as I pull and process one command at a time, so it was crashing my app, plus getting out of sync since that number of bytes never came.

I hardcoded message length 1 for incoming message 95 and I am running again.
Just wanted to post this issue and see if it is a known bug.

The GTT 7 is not being discontinued/replaced I hope?
I saw the contact before ordering notes on all the 7 inch models.

Matrix Orbital
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Re: Load Bitmap return message missing a byte

Post by Clark » Mon Mar 30, 2015 8:27 am

Hi David,

I appreciate you bringing that issue to our attention. I did a quick test this morning, loading the start screen (Logo70A.bmp) into slot 1, and I did receive the correct 252 95 0 1 254 response back from the unit using the Support Tool.

If you could provide your firmware version and any additional details required, I'll try to more accurately replicate your conditions here.

As for the GTT70A, don't worry, we're simply updating the PCB to accommodate options for a capacitive touch screen and lower voltage input.

Troy Clark
Design & Development
Matrix Orbital

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