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98 lines
2.1 KiB
98 lines
2.1 KiB
/** @file tdmdemo2.c
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@author M. P. Hayes, UCECE
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@date 10 August 2011
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@brief Time division multiplexing of display demo
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@defgroup tdmdemo2 Time division multiplexing of display demo
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*/
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#include "system.h"
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#include "pacer.h"
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#include "navswitch.h"
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#include "ledmat.h"
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/* Define polling rate in Hz. */
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#define LOOP_RATE 1000
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int main (void)
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{
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uint8_t col = 0;
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uint8_t tick = 0;
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uint8_t refresh_rate = 1;
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uint16_t update_period;
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system_init ();
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ledmat_init ();
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navswitch_init ();
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pacer_init (LOOP_RATE);
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update_period = LOOP_RATE / (LEDMAT_COLS_NUM * refresh_rate);
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/* Paced loop. */
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while (1)
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{
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/* Wait for next tick. */
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pacer_wait ();
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navswitch_update ();
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if (navswitch_push_event_p (NAVSWITCH_EAST))
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{
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refresh_rate++;
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update_period = LOOP_RATE / (LEDMAT_COLS_NUM * refresh_rate);
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}
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if (navswitch_push_event_p (NAVSWITCH_WEST) && refresh_rate > 0)
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{
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/* Allow refresh_rate to go to zero so can stop display
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refreshing. */
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refresh_rate--;
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update_period = LOOP_RATE / (LEDMAT_COLS_NUM * refresh_rate);
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}
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tick++;
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if (tick >= update_period)
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{
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tick = 0;
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/* Display an 'H' character by time division multiplexing
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the columns of the LED matrix. */
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switch (col)
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{
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case 0:
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ledmat_display_column (0x7f, 0);
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break;
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case 1:
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ledmat_display_column (0x08, 1);
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break;
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case 2:
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ledmat_display_column (0x08, 2);
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break;
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case 3:
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ledmat_display_column (0x08, 3);
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break;
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case 4:
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ledmat_display_column (0x7f, 4);
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break;
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default:
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break;
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}
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col++;
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if (col >= LEDMAT_COLS_NUM )
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col = 0;
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}
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}
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return 0;
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}
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