PWM Disp
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023708f6d0
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1 changed files with 52 additions and 63 deletions
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@ -1,8 +1,8 @@
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#include "LPC17xx.h"
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#include "LPC17xx.h"
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// PWM variables
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// PWM variables
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unsigned long int duty_cycle = 0;
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volatile unsigned long int duty_cycle = 10; // Start at 10%
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unsigned long int pwm_counter = 0;
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volatile unsigned long int pwm_counter = 0;
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// Pin definitions
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// Pin definitions
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#define LED_SHIFT 4 // CNA: P0.4-P0.11
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#define LED_SHIFT 4 // CNA: P0.4-P0.11
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@ -18,10 +18,12 @@ unsigned long int pwm_counter = 0;
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#define COL_MASK_P0 (COL2 | COL3)
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#define COL_MASK_P0 (COL2 | COL3)
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#define COL_MASK_P2 (COL0 | COL1)
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#define COL_MASK_P2 (COL0 | COL1)
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#define PWM_PERIOD 100 // Smaller for faster PWM
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#define PWM_PERIOD 100 // 100 steps for percentage
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static void short_delay(volatile unsigned int d) {
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static void delay_ms(unsigned int ms) {
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while(d--) __NOP();
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unsigned int i, j;
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for(i = 0; i < ms; i++)
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for(j = 0; j < 10000; j++);
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}
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}
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static void set_column(unsigned int col)
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static void set_column(unsigned int col)
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@ -42,12 +44,12 @@ static unsigned int is_row0_pressed(void)
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return !(LPC_GPIO0->FIOPIN & ROW0);
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return !(LPC_GPIO0->FIOPIN & ROW0);
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}
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}
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// PWM Interrupt Handler - Software PWM
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// HIGH-SPEED PWM Interrupt Handler
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void PWM1_IRQHandler(void)
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void PWM1_IRQHandler(void)
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{
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{
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if (LPC_PWM1->IR & (1 << 0))
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if (LPC_PWM1->IR & (1 << 0))
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{
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{
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// Software PWM for all 8 LEDs
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// Fast software PWM for all 8 LEDs
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if(pwm_counter < duty_cycle)
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if(pwm_counter < duty_cycle)
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LPC_GPIO0->FIOSET = LED_MASK; // All LEDs ON
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LPC_GPIO0->FIOSET = LED_MASK; // All LEDs ON
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else
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else
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@ -57,72 +59,71 @@ void PWM1_IRQHandler(void)
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if(pwm_counter >= PWM_PERIOD)
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if(pwm_counter >= PWM_PERIOD)
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pwm_counter = 0;
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pwm_counter = 0;
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LPC_PWM1->IR = (1 << 0); // Clear interrupt
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LPC_PWM1->IR = (1 << 0); // Clear interrupt flag
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}
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}
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}
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}
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int main(void)
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int main(void)
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{
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{
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unsigned int col_idx;
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unsigned int col_idx;
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unsigned int candidate_key = 0xFF;
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unsigned int read_key;
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unsigned int stable = 0;
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unsigned int last_key = 0xFF;
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unsigned int last_key = 0xFF;
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// === SYSTEM CLOCK SETUP (Optional but recommended) ===
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SystemInit(); // Use default clock setup
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// === PIN CONFIGURATION ===
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// === PIN CONFIGURATION ===
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LPC_PINCON->PINSEL0 &= ~(0xFFFF << 8); // Clear P0.4-P0.11 (GPIO)
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LPC_PINCON->PINSEL0 &= ~(0xFFFF << 8); // P0.4-P0.11 as GPIO
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LPC_PINCON->PINSEL1 &= ~(0xFFFF << 14); // Clear P0.23-P0.28
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LPC_PINCON->PINSEL1 &= ~(0xFFFF << 14); // P0.23-P0.28 as GPIO
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LPC_PINCON->PINSEL3 &= ~(0x3 << 14); // Clear P1.23
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LPC_PINCON->PINSEL4 &= ~(0xF << 0); // P2.0-P2.1 as GPIO
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LPC_PINCON->PINSEL4 &= ~(0xF << 0); // Clear P2.0-P2.1
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// === GPIO DIRECTION SETUP ===
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// === GPIO SETUP ===
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LPC_GPIO0->FIODIR |= LED_MASK; // P0.4-P0.11: LEDs (output)
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LPC_GPIO0->FIODIR |= LED_MASK; // LEDs output
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LPC_GPIO0->FIODIR |= COL_MASK_P0; // Keypad columns (output)
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LPC_GPIO0->FIODIR |= COL_MASK_P0; // Columns output
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LPC_GPIO2->FIODIR |= COL_MASK_P2; // Keypad columns (output)
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LPC_GPIO2->FIODIR |= COL_MASK_P2; // Columns output
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LPC_GPIO0->FIODIR &= ~ROW0; // Row-0 (input)
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LPC_GPIO0->FIODIR &= ~ROW0; // Row input
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// === INITIALIZE GPIO ===
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// Initialize
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LPC_GPIO0->FIOCLR = LED_MASK; // All LEDs off initially
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LPC_GPIO0->FIOCLR = LED_MASK;
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LPC_GPIO2->FIOSET = COL_MASK_P2; // Columns high
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LPC_GPIO2->FIOSET = COL_MASK_P2;
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LPC_GPIO0->FIOSET = COL_MASK_P0; // Columns high
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LPC_GPIO0->FIOSET = COL_MASK_P0;
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// === PWM CONFIGURATION ===
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// === HIGH-SPEED PWM CONFIGURATION ===
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LPC_SC->PCONP |= (1 << 6); // Power on PWM1
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LPC_SC->PCONP |= (1 << 6); // Power on PWM1
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LPC_PWM1->TCR = (1 << 1); // Reset PWM
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LPC_PWM1->TCR = (1 << 1); // Reset
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LPC_PWM1->CTCR = 0; // Timer mode
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LPC_PWM1->CTCR = 0; // Timer mode
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LPC_PWM1->PR = 99; // Prescaler: divide by 100
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LPC_PWM1->PR = 9; // Prescaler = 10
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// Creates ~10kHz interrupt rate
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// 100MHz / 10 = 10MHz timer clock
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LPC_PWM1->MR0 = PWM_PERIOD; // PWM period = 100
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LPC_PWM1->MR0 = 100; // Match every 100 ticks
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LPC_PWM1->MR4 = 0; // Duty cycle = 0
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// Interrupt rate = 10MHz/100 = 100kHz
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// PWM frequency = 100kHz/100 = 1kHz
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// NO VISIBLE FLICKER!
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LPC_PWM1->MCR = (1 << 1) | (1 << 0); // Reset on MR0, interrupt enabled
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LPC_PWM1->MCR = (1 << 1) | (1 << 0); // Reset on MR0 + interrupt
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LPC_PWM1->LER = (1 << 0); // Latch MR0
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LPC_PWM1->LER = (1 << 0); // Latch MR0
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NVIC_EnableIRQ(PWM1_IRQn); // Enable PWM interrupt
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NVIC_EnableIRQ(PWM1_IRQn); // Enable interrupt
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NVIC_SetPriority(PWM1_IRQn, 0); // Highest priority
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NVIC_SetPriority(PWM1_IRQn, 0); // Highest priority
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LPC_PWM1->TCR = (1 << 0) | (1 << 3); // Enable PWM and counter
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LPC_PWM1->TCR = (1 << 0) | (1 << 3); // Start PWM
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// Initial duty cycle: 10%
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duty_cycle = 10;
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// === MAIN LOOP ===
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// === MAIN LOOP ===
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while(1)
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while(1)
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{
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{
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unsigned int read_key = 0xFF;
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read_key = 0xFF;
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// Scan ROW-0 (keys 0, 1, 2, 3)
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// Scan ROW-0 only
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for(col_idx = 0; col_idx < 4; col_idx++)
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for(col_idx = 0; col_idx < 4; col_idx++)
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{
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{
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set_column(col_idx);
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set_column(col_idx);
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short_delay(500);
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delay_ms(5); // Short delay for stable reading
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if(is_row0_pressed()) {
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if(is_row0_pressed()) {
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read_key = col_idx;
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read_key = col_idx; // Key 0, 1, 2, or 3
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// Wait for key release
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while(is_row0_pressed()) {
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delay_ms(10);
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}
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break;
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break;
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}
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}
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}
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}
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@ -131,30 +132,18 @@ int main(void)
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LPC_GPIO2->FIOSET = COL_MASK_P2;
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LPC_GPIO2->FIOSET = COL_MASK_P2;
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LPC_GPIO0->FIOSET = COL_MASK_P0;
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LPC_GPIO0->FIOSET = COL_MASK_P0;
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// Debounce
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// Update brightness immediately on key press
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if(read_key == candidate_key) {
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if(read_key != 0xFF && read_key != last_key) {
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if(stable < 5) stable++;
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last_key = read_key;
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} else {
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candidate_key = read_key;
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stable = 1;
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}
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// Update intensity when stable
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switch(read_key) {
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if(stable >= 5) {
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case 0: duty_cycle = 10; break; // 10%
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if(candidate_key != last_key && candidate_key != 0xFF) {
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case 1: duty_cycle = 25; break; // 25%
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last_key = candidate_key;
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case 2: duty_cycle = 50; break; // 50%
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case 3: duty_cycle = 75; break; // 75%
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// Set duty cycle (out of 100)
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switch(candidate_key) {
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case 0: duty_cycle = 10; break; // 10%
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case 1: duty_cycle = 25; break; // 25%
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case 2: duty_cycle = 50; break; // 50%
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case 3: duty_cycle = 75; break; // 75%
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}
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}
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}
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stable = 5;
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}
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}
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short_delay(5000);
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delay_ms(50); // Main loop delay
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}
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}
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}
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}
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