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--- dseq32_matrix [2006/09/23 00:53] – mess
+++ dseq32_matrix [2006/10/15 09:35] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
+This page will contain the information about the combined lcd/button matrix
+[[http://www.midibox.org/forum/index.php?topic=7087.0|forum topic]]<sup>uCApps</sup>
+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 [[http://www.ucapps.de/mios/sm_example1_v2.zip|scan matrix example]] <sup>uCApps</sup>\\
+==== Hardware ====
+[[http://users.skynet.be/sky92755/DSEQ32_DOUT.pdf|DOUT wiring]]\\
+\\
+[[http://users.skynet.be/sky92755/DSEQ32_DIN.pdf|DIN wiring]]\\
+//*note: schematics not finished!//\\
+==== Software ====
+in main.c:\\
+<code>
+...
+//second shiftregister drives the leds
+#define LEDOUT 1
+...
+void LM_SetRow(){
+	MIOS_DOUT_SRSet(LEDOUT,ledtest[sm_col]);
+}
+/////////////////////////////////////////////////////////////////////////////
+// This function is called by MIOS before the shift register are loaded
+/////////////////////////////////////////////////////////////////////////////
+void SR_Service_Prepare(void) __wparam
+{
+  // call the Scan Matrix Driver
+  SM_PrepareCol();
+  // call the Led Matrix Driver
+  LM_SetRow();
+}
+...
+</code>
+\\
+in sm_simple.asm:
+<code>
+...
+	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
+...
+SM_PrepareCol
+	;; 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)
+...
+</code>
+\\
+and finally in sm_simple.h:
+<code>
+...
+extern unsigned char sm_button_value;
+extern unsigned char sm_col;
+...
+</code>
+==== Appendum ====
+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!!!
+== Workaround ==
+To turn the debouncing off, set
+<code>
+#define DIN_DEBOUNCE_VALUE    0
+</code>
+back to [[DSEQ32]]