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This page will contain the information about the combined lcd/button matrix forum topicuCApps

right now I'm using a modified version of the sm_simple C example
this code will be rewritten to make it more coherent

modifications to scan matrix example uCApps


DOUT wiring

DIN wiring

*note: schematics not finished!


in main.c:

//second shiftregister drives the leds
#define LEDOUT 1
void LM_SetRow(){

// This function is called by MIOS before the shift register are loaded
void SR_Service_Prepare(void) __wparam
  // call the Scan Matrix Driver
  // call the Led Matrix Driver

in sm_simple.asm:

	global	_sm_button_column
	global	_sm_button_row
	global	_sm_button_value
	global  _sm_col

	;; import lables
	extern	_SM_NotifyToggle

; ==========================================================================

accessram		udata		; (no access ram required, these variables can be located anywhere)

_sm_button_column	res	1	; exported to C, therefore an "_" has been added
_sm_button_row		res	1
_sm_button_value	res	1
_sm_col				res 1


	;; select next DOUT register

	;; (current column + 1) & 0x07
	SET_BSR	sm_selected_column
	incf	sm_selected_column, W, BANKED	; (* see note below)
	andlw	0x07
	;_sm_col is used by LM_SetRow()
	movwf	_sm_col
	call	MIOS_HLP_GetBitANDMask	; (inverted 1 of 8 code)

and finally in sm_simple.h:

extern unsigned char sm_button_value;
extern unsigned char sm_col;


To avoid flickering leds when pushing a button the MIOS button debouncing should be turned off!!

Due to the setup of the SRIO driver the debounce algoritm also delays the DOUT chain when a DIN event is being debounced. So when a button is pushed the led update frequency is reduced, the higher the debounce value, the lower the update frequency.

According to this post TK will fix this in a future MIOS release:

This is something what I'm planning to solve in one of the next MIOS versions - currently the same SR scanning routine is used for DIN and DOUT registers, which means, >when the DINs are temporary disabled due to the cheap debouncing method, the DOUT registers won't be updated.

The solution is to add a second scan routine which only services the DOUTs so long the debouncing delay is active.

In the meantime THIS ISSUE IS SOLVED WITH MIOS1.9c!!!


To turn the debouncing off, set


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dseq32_matrix.txt · Last modified: 2006/10/15 09:35 (external edit)