60 lines
1.8 KiB
C
60 lines
1.8 KiB
C
#include "lcd_clock.h"
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// Breaks down the give time of day in seconds into a tod_t struct
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tod_t time_breakdown(int time_of_day_sec){
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int tod_hours = time_of_day_sec / 3600;
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int ispm = tod_hours >= 12 ? 1 : 0;
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tod_hours = tod_hours % 12;
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tod_hours = tod_hours == 0 ? 12 : tod_hours;
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int tod_minutes = (time_of_day_sec / 60) % 60;
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int tod_seconds = time_of_day_sec % 60;
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tod_t tod = {.hours = tod_hours,
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.minutes = tod_minutes,
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.seconds = tod_seconds,
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.ispm = ispm};
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return tod;
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}
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// Binary masks for each digit for ease of setting
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int digit_masks[10] = {
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0b0111111, // zero
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0b0000110, // one
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0b1011011, // two
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0b1001111, // three
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0b1100110, // four
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0b1101101, // five
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0b1111101, // six
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0b0000111, // seven
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0b1111111, // eight
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0b1101111, // nine
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};
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#define BLANK 0b0000000 // blank
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#define AM_MASK (0x1 << 28)
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#define PM_MASK (0x1 << 29)
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int display_bits_from_tod(tod_t tod){
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int hr_tens = tod.hours >= 10 ? digit_masks[1] : BLANK;
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int hr_ones = digit_masks[tod.hours % 10];
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int mn_tens = digit_masks[tod.minutes / 10];
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int mn_ones = digit_masks[tod.minutes % 10];
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int ampm = tod.ispm ? PM_MASK : AM_MASK;
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int state = 0;
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state |= (mn_ones << 0);
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state |= (mn_tens << 7);
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state |= (hr_ones << 14);
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state |= (hr_tens << 21);
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state |= ampm;
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return state;
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}
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/* Examine the TIME_OF_DAY_SEC to determine hour, minute, and am/pm.
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Set the LCD_DISPLAY_PORT bits to show the proper time. */
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void lcd_update(){
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tod_t tod = time_breakdown(TIME_OF_DAY_SEC);
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int state = display_bits_from_tod(tod);
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LCD_DISPLAY_PORT = state;
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}
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