79 lines
2.3 KiB
C
79 lines
2.3 KiB
C
#include <LPC17xx.h>
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const unsigned char seven_seg[16] = {
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0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,
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0x7F,0x6F,0x77,0x7C,0x39,0x5E,0x79,0x71
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};
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#define SEG_SHIFT 4
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#define DIGIT_ENABLE_P1 (1<<23)
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#define DIGIT_ENABLE_MASK (0x0F<<23)
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#define COL_BASE_BIT 15
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#define ROW_BASE_BIT 19
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#define COL_MASK ((0x0F) << COL_BASE_BIT)
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#define ROW_MASK ((0x0F) << ROW_BASE_BIT)
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static void short_delay(volatile unsigned int d){ while(d--) __NOP(); }
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int main(void){
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unsigned int col_idx,row_idx;
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unsigned int candidate = 0xFF;
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unsigned int stable = 0;
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unsigned int displayed = 0xFF;
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unsigned int row_bits;
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LPC_PINCON->PINSEL0 &= ~(0xFFFFFFFF);
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LPC_PINCON->PINSEL1 &= ~(0xFFFFFFFF);
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LPC_GPIO0->FIODIR |= (0xFF << SEG_SHIFT);
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LPC_GPIO0->FIODIR |= COL_MASK;
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LPC_GPIO0->FIODIR &= ~ROW_MASK;
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LPC_GPIO1->FIODIR |= DIGIT_ENABLE_MASK;
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LPC_GPIO0->FIOPIN &= ~(0xFF << SEG_SHIFT);
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LPC_GPIO1->FIOPIN &= ~DIGIT_ENABLE_MASK;
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LPC_GPIO0->FIOSET = COL_MASK;
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for(;;){
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unsigned int read_key = 0xFF;
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for(col_idx=0; col_idx<4; col_idx++){
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LPC_GPIO0->FIOSET = COL_MASK;
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short_delay(50);
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LPC_GPIO0->FIOCLR = (1 << (COL_BASE_BIT + col_idx));
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short_delay(200);
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row_bits = (LPC_GPIO0->FIOPIN & ROW_MASK) >> ROW_BASE_BIT;
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if(row_bits != 0x0F){
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for(row_idx=0; row_idx<4; row_idx++){
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if((row_bits & (1<<row_idx)) == 0){
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read_key = col_idx*4 + row_idx;
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break;
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}
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}
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LPC_GPIO0->FIOSET = COL_MASK;
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break;
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}
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LPC_GPIO0->FIOSET = COL_MASK;
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}
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if(read_key == candidate){
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if(stable < 3) stable++;
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} else {
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candidate = read_key;
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stable = 1;
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}
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if(stable >= 3){
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if(candidate != 0xFF){
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displayed = candidate & 0x0F;
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}
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stable = 3;
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}
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if(displayed != 0xFF){
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unsigned int seg = seven_seg[displayed];
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LPC_GPIO0->FIOCLR = (0xFF << SEG_SHIFT);
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LPC_GPIO0->FIOSET = (seg << SEG_SHIFT);
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LPC_GPIO1->FIOCLR = DIGIT_ENABLE_MASK;
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LPC_GPIO1->FIOSET = DIGIT_ENABLE_P1;
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}
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short_delay(3000);
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}
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}
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