Enable case light menu, no pwm

[frenck]

Description

Some small fixes for running a BTT TFT. This enables the case light menu on the LCD. Also, disables brightness control, as pwm doesn't seem to work/be supported.

Benefits

Ability to control the hotend LED with the screen.

Configurations

The PR adjusts just that...

Related Issues

None.

[Sebazzz]

I didn't enable the case light because it isn't a light, but as you have seen, seems not possible to control the LED otherwise.
Admittedly I haven't tried the brightness, but on Creality boards it does work.

[frenck]

Well, "isn't a light" is debatable, as it is an LED that emits electromagnetic radiation within the range of the electromagnetic spectrum that can be seen by the human eye... 😉

Nevertheless, yeah, the latest firmware turned the LED on the hotend off by default, which is fine (I remember this being the default for the Creality firmware as well). The problem is indeed, that you cannot turn it on with the display controls. Hence me activating this menu. Another option would be a
custom script (which, IMHO is hackier).

As for PWM controls, I've tried, but the firmware/light didn't respond to it on my CR-6 SE, with BTT board and BTT TFT, hence I've disabled it. It doesn't change the behavior prior to this PR and doesn't add a non-working item to the menu either.

So, yeah, this simply provides the possibility to turn it on or off via the display.

[Sebazzz]

Well, "isn't a light" is debatable, as it is an LED that emits electromagnetic radiation within the range of the electromagnetic spectrum that can be seen by the human eye... 😉

Yes I meant to say, it isn't first class in Marlin even though the gcode for direct pin control falls back on LED_CONTROL_PIN by default.