need advise to do 16*16 butons matrix

[moxi]

hi,

someone ask me how to do a 16*16 matrix,

looking to the sm example v1, i've found two point where change have to be made, iwant to know if it's the only point i need to make change:

first , in sm_simple.inc:

* at "SM_GetRow" :

;; increment column, wrap at 8 <--- i want to wrap at 16, right?

incf SM_SELECTED_COLUMN, W, BANKED

andlw 0x07                            <------------so, here i change 0x07 by 0x0f, right?

movwf SM_SELECTED_COLUMN, BANKED

* at "SM_ButtonHandler_Loop"

"""IFSET        INDF0, 7, rcall SM_NotifyToggle_Pin7 """  --> here, go on the intruction to :

"""IFSET INDF0, 15, rcall SM_NotifyToggle_Pin15"""

* at "SM_ButtonHandler_Loop_Next":

incf SM_BUTTON_COLUMN_CTR, F, BANKED

movlw 0x10-1 ; (16 columns)<------change here

*at :

"" SM_NotifyToggle_Pin0 ---> go on with this instructuction to "SM_NotifyToggle_Pin15"  ""

will this change be suffisant ?

thanks

[TK.]

Hi Moxi,

My proposal: just try it out, there are always cases which nobody do consider, regardless how often they look into the code (it's also my own problem - therefore I cannot release variations without the possibility to try it with the appr. hardware)

Best Regards, Thorsten.

[moxi]

hi,

ok, i will try to add some more line of button to my already build matrix..and spend more time in the code..but if someone have do such experience, tell us what you report...

and i suppose that if you don't say "impossible" ,it's cause that's possible! ;)

[TK.]

I think that even driving a matrix with let's say 1024 buttons (via 1 DOUT and 4 DINs) is not impossible, it's only a question of RAM consumption and desired latency

Best Regards, Thorsten.