Uart and sp1 communication on lcd screen types

Hi, i recently got referred to the forum here after asking about lcds. I more or less finally found a resonable answer to my question in an offhand way and decided to share what i found.
My older Tevi Tarantula Pro printer came with many upgrades possible from stock and I started several years ago doing it. First dual z and printing filament stands, etc .i had purchased a makerbase tft28 lcd screen to upgrade from the stock 12864 screen.
Using the new screen i tried endlessly to get any of the uart settings for on the fly rtuning with no luck for options showing on the screen befire or after reflashing the marlin firmware.
I wanted a better screen but couldnt find anywhere a screen that stated it could show the uart settings?
So I think the answer is that the uart and sp1 languages are 2 different ways for the drivers to communicate withe the rest of the biard and peripherals. So, as it turns out, sp1 is the older language and a serial connection that can send the contents by character syream to your lcd and thus uart settings can be displayed on screen.
On the other hand the touch lcd screens use a language to send/receive data values, not screen text to the lcd. If you have the option in the lcd to receive the value, then it shows up if the option isnt pre programmed on the screen then the value obviously has nowhere to be displayed
Now there are screens that allow both types oof communication but you still need to change back and forth between the type of communication on the screen.
Let me kniw any discrepancies anyone notices, thanks

You didn’t say what type of controller board you’re running and how your are connecting.

Did you look at the MKS GitHub page for the UI? You didn’t say which version you have, so you’ll have to figure out which is the right one for you:

I have the tft 2.8 and it is the same firmware for all those mks tft lcd screens. Options are limited, besides aesthetically, to custom buttins but you would need to know specific commands. With the uart on the marlin firmware, you basucally enable uart settings and certain settings will show on the sp1 screen such as print speed, flow speed, temperature adjustments. As well as any variable values such as jerk settings, auto bed levelling settings, preheat settings, levelling settings, etc. None of those settings will show up on the touch screens that dont use the sp1 communication from enabling them in you mainboard firmware. You also need certain drivers for your mainboard that are capable of the uart.
The uart settings allow fine tuning of the hardware settings in the firmware from the screen as opposed to reflashing firmware each time you need change a value.
The firmware for the touch lcd screens is basic and virtually doesnt talk to your mainboard, it only can change settings that you have flashed onto it.
Sorry about spelling in first post, i reread this one.
I was trying to point out what was needed for the uart settings since thise settings are an easier user interface then sending gcide comnands.
The uart settings can save your tuning too so you dont have to redo values each time you power on your printer.

You didn’t answer my questions:

You didn’t say what type of controller board you’re running and how your are connecting.

From what I gathered from your original post you weren’t getting anything at all on the LCD and first wanted to understand what is the controller in your printer so I can understand what are the connectors on it and then I wanted to understand the cabling. With this information, I would like to understand your pin assignments so that I know what MCU pins are being connected to which LCD pins.