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Wokwi Feature requests & Bug Reports
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ILI9341 emulation does not respect RGB pixel order #413

Closed ivmarkov closed 9 months ago

ivmarkov commented 1 year ago

Describe the bug The ILI9341 emulator always assumes BGR order, when - in fact - this is configurable via the 0x36 "Memory Access Control" command (see page 127, section 8.2.29, bit BGR here.

To Reproduce

Difficult to reproduce without too much setup. The reason is, your demo is based on the AdaFruit Arduino library, which - when looking at the code - always requests BGR order with the 0x36 command (bit BGR set = 0x08) as evidenced here and perhaps you just assume and hard-code to BGR without inspecting that bit.

Unfortunately there are other codebases that request RGB order and then assume and hard-code and interpret the order as RGB, but since the BGR bit seems not to be respected, I get reordered colors (blue instead of red).

Upon request, I can provide a smaller binary for ESP32 & Rust that demos the problem, but I think the issue is pretty straightforward.

Expected behavior The emulator should examine the BGR bit in command 0x36 and interpret the colors appropriately (either as BGR or RGB, depending on what the user had requested).

Environment (please complete the following information):

Additional context I've seen other issues as well, but too early to comment on those as the root cause is still unclear. Like the CS pin being hard-wired to GPIO15 or else it does not work (why?). Also the performance is pretty bad. But more on these when/if I'm able to nail down the root cause.

urish commented 1 year ago

Thanks for the detailed report!

The ILI9341 does support the BRG/RGB bit, we added it two months ago. As far as I remember, it was specifically for the rust use case.

I'm not sure why it doesn't work for you, but if you could provide a reproduction that would be helpful in figuring it out.

ivmarkov commented 1 year ago

Thanks. I'm using something called "Wokwi Embedded Alpha" if that's of any help (basically, a web service that allows me to submit a binary firmware, completely bypassing the Arduino stuff).

Is the above running the latest emulation code?

Regardless, I might find a little time tmr to provide a binary + simple sketch. Thanks again!

urish commented 1 year ago

Is the above running the latest emulation code?

It does

Regardless, I might find a little time tmr to provide a binary + simple sketch. Thanks again!

This will be very helpful. Or a gitpod workspace with the source code + Wokwi Embedded Alpha setup

urish commented 9 months ago

Closing as this hasn't been active for over a year.