update keyboard leds

[bubach]

Hello, i recently added code in my keyboard irq to update teh leds when caps, num or scroll lock is pressed..

the problem is that bosch gives me a "keyboard buffer full"-error when i have this function enabled..

something i am missing?
thanks in advance..

/ Christoffer

[distantvoices]

i wouldn't do this kind of operation in the isr. I'd do it in a sort of task - or a tasklet, which does the work after the isr has fetched the scancodes from kbd port 60 (iirc)

are you still reading scancodes from port 60?

If not, no wonder that bochs doesn't like it.

are you issueing the correct combo of command/data sequence? I don't know it by heart, but can lookup.

is your code caught in a condition which never/always becomes true?

just check it out. Without more info about *how* your kbd isr looks like (a rough sketch in human language or pseudocode suffices), we canna give that much help as we want to.

ha en bra dag

[bubach]

Hmm. I?ll try to describe the process..

I read the scan code from port 0x60

I check if key is released or pressed. save status as bit in "special-byte"
If ctrl is pressed or not, saved as bit in the "special-byte"
if shift - ||-
if alt - || -
if ctrl+alt+del is pressed, add bit in special-byte..

if caps is pressed, save status in "status-byte"
if num - || -
if scroll - || -

at the end i add the scan code to a buffer, and updates the status and special bytes, after that i "call update_leds" and exits the isr as usual; ack to pic(?) with out 0x20 something..

the update_leds function is adapted from a swedish os, that have a keyboard isr that looks almost excatly like mine.
it sends some bytes (the status-byte and maybe something else) and call a simple "kbd_wait" function 2(?) times in between..

to bad i don?t have my source with me..

[edit] to cold in sweden right now for a "bra dag" (eng: good day)..

[distantvoices]

Below are the crucial pieces of code from my own kbd led handling.

Basically you send a bitmask to the controller which tells, which led is on and which one is off.

How are you setting the corresponding bit in status byte say for caps lock?

Code: Select all

void kbd_ack(void){ 
  while(!(inport(0x60)==0xfa));
}


void kbd_led_handling(uchar_t ledstatus){;
  outport(0x60,0xed); 
  kbd_ack();
  outport(0x60,ledstatus);
}

Here in vienna, sun shines but it is cooold as in devils arse.

But that shall not hinder us from enjoying a biiig snow feast.

[bubach]

hmm. can?t remeber the right order right now, but its something like:
bit 1= 1 for num on, 0 for num off
bit 2= 1 for scroll on, 0 for scroll off
bit 3= 1 for caps on, 0 for caps off
bits 4-8 = 0

i think thats how it?s done.. but as i don?t have my sources right here...

[bubach]

Okay, now i have my source.
Lets see.. Here?s how i check and set the bits in the "kbd_status" byte... (u can?t turn them of yet..)

Code: Select all

;----------------------;
;   Keyboard IRQ         ;
;----------------------;
keyboard_isr:
          push    eax
     ;-----------------------------------;
     ; get the scancode and statusbyte   ;
     ;-----------------------------------;
          xor     eax, eax
          in      al, 0x60
          mov     ah, byte [kbd_special]    ; for ctrl+alt+del etc..

     ;------------------------------;
     ;  check if key was released   ;
     ;------------------------------;
          test    al, 0x80
          jz      .key_down
          or      ah, 10000000b 

;............... some code..............

     ;----------------------------------------------;
     ;  a key was pressed, check for special keys   ;
     ;----------------------------------------------;
     .key_down:
          and     ah, 01111111b     

;............... some code..............

     .check_caps:
          cmp     al, 58
          jnz     .check_num
          or      byte [kbd_status], 00000100b
          jmp     .end

     .check_num:
          cmp     al, 69
          jnz     .check_scroll
          or      byte [kbd_status], 00000010b
          jmp     .end

     .check_scroll:
          cmp     al, 70
          jnz     .end
          or      byte [kbd_status], 00000001b
          jmp     .end 

;.............. some more code...................

    .end:
          mov     [kbd_raw_buffer], al
          mov     [kbd_special], ah


          movzx   eax, [kbd_status]  ; to check if the statusbyte was correct..
          call    print_hex32


;          call    update_leds

          mov     al, 0x20
          out     0x20, al
          pop     eax
          ret

the (current) update_leds function

Code: Select all

;------------------------------;
;  Update the keyboard LED?s   ;
;------------------------------;
update_leds:
          push    ax

     .l1:
          in      al, 0x64
          and     al, 0x02
          jnz     .l1

          mov     al, 0xED
          out     0x60, al

     .l2:
          in      al, 0x64
          and     al, 02
          jnz     .l2

          mov     al,[kbd_status]
          out     0x60, al

          pop     ax
          ret

Do you have any links to information about "advanced" keyboard programming? Becasue i would also like to know how to test the type of keyboard, know how to set diffrent "scan-modes(?) etc.

/ Christoffer

[bubach]

[EDIT] For future forum viewers with the same problem, i now update this post with the correct and fully working code..

variable defined:

Code: Select all

     ;-------------------------------------------------------------------------;
     ; _________________        LED status byte:                               ;
     ; |0|0|0|0|0|1|1|1|                                                       ;
     ; +---------------+                     1 = True   0 = False              ;
     ;            | | +--->  scroll lock                                       ;
     ;            | +----->  num lock                                          ;
     ;            +------->  caps lock                                         ;
     ;-------------------------------------------------------------------------;
     kbd_status     db   0            ; LED statusbyte

In the keyboard IRQ:

Code: Select all

     ;-------------------------------------;
     ;  toggle caps, num and scroll lock   ;
     ;-------------------------------------;
     .check_caps:
     cmp     al, 58
     jnz     .check_num
     xor     byte [kbd_status], 4
     call     update_leds
     jmp     .end

     .check_num:
     cmp     al, 69
     jnz     .check_scroll
     xor     byte [kbd_status], 2
     call     update_leds
     jmp     .end

     .check_scroll:
     cmp     al, 70
     jnz     .end
     xor     byte [kbd_status], 1
     call     update_leds
     jmp     .end

And the functions required to change the LEDs:

Code: Select all

;------------------------------;
;  Update the keyboard LED?s   ;
;------------------------------;
update_leds:
     push     ax

     call     kbd_wait

     mov     al, 0xED
     out     0x60, al

     call     kbd_wait

     mov     al, [kbd_status]
     out     0x60, al

     call     kbd_wait

     pop     ax
     ret



;------------------;
;  keyboard wait   ;
;------------------;
kbd_wait:
     jmp     $+2
     in     al,64h
     test     al,1
     jz     .ok
     jmp     $+2
     in     al,60h
     jmp     kbd_wait
     .ok:
     test     al,2
     jnz     kbd_wait
     ret

anyway, thanks for the help and major input..

/ Christoffer