This is an old revision of the document!
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
Hardware
*note: schematics not finished!
Software
in main.c:
...
//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();
}
...
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 ... 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) ...
and finally in sm_simple.h:
... extern unsigned char sm_button_value; extern unsigned char sm_col; ...
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.
Workaround
