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Why is ESP32-S3 LCD Module limited to 16 Bit?

Posted: Fri Jul 29, 2022 9:27 am
by Tobi82m
Hello,

i need a 24 Bit parallel Data Stream. With ESP32 and the I2S Module i cant generate a 24 Bit Stream, but the ESP32 has not enough pins.
Now with the ESP32-S3 i have enough pins, but i can only generate a 16 Bit Stream with the LCD Module. But why? Is there any hardware limitation?

Re: Why is ESP32-S3 LCD Module limited to 16 Bit?

Posted: Sat Jul 30, 2022 2:48 am
by ESP_Sprite
Yes. The LCD peripheral is only designed for up to 16-bit displays.

Re: Why is ESP32-S3 LCD Module limited to 16 Bit?

Posted: Tue Aug 02, 2022 3:42 am
by ESP_morris
FWIW, ESP32-S3 also supports Serial RGB interface, where you only need 8 data GPIOs to transfer RGB888 data.

Re: Why is ESP32-S3 LCD Module limited to 16 Bit?

Posted: Thu Aug 04, 2022 1:07 pm
by Tobi82m
My Problem is, i dont want to use it for LCD Data. I want to send 24bit Data, read from a File, to a Hardware that reads 2x12Bit parallel data stream. With ESP32 it works perfekt. There only problem is there are not 24 GPIOs.
So i think i to to a ESP32-S2, which has enough PINS...but ESP32-S2 has only one Core...sending 24bit parallel with 2 Mhz corrupts with one core

Re: Why is ESP32-S3 LCD Module limited to 16 Bit?

Posted: Fri Aug 05, 2022 1:01 am
by ESP_Sprite
Sorry, the only way around that would be to add something external to make the bus wider... you could have something like a set of latches that clock in the data at even/odd cycles and interleave the data that way, for instance, or depending on the speed you could forego the LCD module and use a SPI and bunch of shift registers to clock the data in.

For what it's worth, we've noted that there is a demand for larger-width parallel outputs for the LCD module, and we'll see if we can include this in as-of-yet unreleased chips that are under development.