CODEWITHSUNDEEP
cassemblykeyboardkernel
user3131007
user3131007

Reputation:

Turn PS/2 keyboard Caps Lock LED on/off in custom kernel

I'm developing a kernel with assembly language and C and in the boot up process, I want the kernel to turn the Caps Lock key on and then off. I have found the reference for the LED on the key here. How could I call that function with C or assembly (NASM style)?

Upvotes: 1

Views: 1390

Answers (2)

Hai Dang
Hai Dang

Reputation: 21

You can read my code for reference:

irq_ex2.c: An interrupt handler example. This code binds itself to IRQ 1, which is the IRQ of the keyboard controlled under Intel architectures. Then, when it receives a keyboard interrupt, it reads the information about the status LED and keycode into the work queue.

Pressing:

  • ESC → Caps Lock LED OFF

  • F1,F2 → Caps Lock ON

Upvotes: 0

sgupta
sgupta

Reputation: 1272

SetKeyBoardLeds:
   push  eax
   mov   al,0xed
   out   60h,al
KeyBoardWait:
   in    al,64h
   test  al,10b
   jne   KeyBoardWait
   mov   al,byte [keyBoardStatus]
   and   al,111b
   out   60h,al
   pop   eax
   ret

For example,

   mov   [keyBoardStatus],0xb0    ; Initialise keyboard LED state
   call  SetKeyBoardLeds
;--------------------------------- This will toggle CapsLock LED
   xor   [keyBoardStatus],4
   call  SetKeyBoardLeds
;---------------------------------
   and   [keyBoardStatus],0xfb
   call  SetKeyBoardLeds

where keyBoardStatus is a byte (it will hold the current keyboard LED state).

Upvotes: 1

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