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PWM Disp

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This commit is contained in:
sherlock 2025-10-23 12:51:02 +05:30
parent 161a7b1ee3
commit d783943935
2 changed files with 201 additions and 42 deletions
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172
ES/Lab/Lab11/PWM_Keyboard.c
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@ -1,70 +1,158 @@
#include "LPC17xx.h"
#include <stdio.h>
// PWM variables
unsigned long int duty_cycle = 0;
unsigned long int new_duty = 0;
int press_count = 0;
unsigned long int pwm_counter = 0;
void delayMs(unsigned int ms)
{
unsigned int i, j;
for (i = 0; i < ms; i++)
for (j = 0; j < 20000; j++);
// Pin definitions based on connectors
#define LED_SHIFT 4 // CNA: P0.4-P0.11 (8 LEDs)
#define LED_MASK (0xFF << LED_SHIFT)
// Keypad on CND - Only ROW-0
#define COL0 (1<<0) // P2.0
#define COL1 (1<<1) // P2.1
#define COL2 (1<<23) // P0.23
#define COL3 (1<<24) // P0.24
#define ROW0 (1<<25) // P0.25 (ROW-0 only)
#define COL_MASK_P0 (COL2 | COL3)
#define COL_MASK_P2 (COL0 | COL1)
static void short_delay(volatile unsigned int d) {
while(d--) __NOP();
}
// Set a specific column low, others high
static void set_column(unsigned int col)
{
// Set all columns high first
LPC_GPIO2->FIOSET = COL_MASK_P2;
LPC_GPIO0->FIOSET = COL_MASK_P0;
// Pull specific column low
switch(col) {
case 0: LPC_GPIO2->FIOCLR = COL0; break;
case 1: LPC_GPIO2->FIOCLR = COL1; break;
case 2: LPC_GPIO0->FIOCLR = COL2; break;
case 3: LPC_GPIO0->FIOCLR = COL3; break;
}
}
// Check if ROW-0 is pressed
static unsigned int is_row0_pressed(void)
{
return !(LPC_GPIO0->FIOPIN & ROW0);
}
// PWM Interrupt Handler
void PWM1_IRQHandler(void)
{
if (LPC_PWM1->IR & (1 << 0))
{
LPC_PWM1->MR4 = new_duty;
LPC_PWM1->LER = (1 << 4);
LPC_PWM1->IR = (1 << 0);
// Software PWM for LEDs (CNA: P0.4-P0.11)
pwm_counter++;
if(pwm_counter >= 3000) pwm_counter = 0;
if(pwm_counter < duty_cycle)
LPC_GPIO0->FIOSET = LED_MASK; // LEDs ON
else
LPC_GPIO0->FIOCLR = LED_MASK; // LEDs OFF
LPC_PWM1->IR = (1 << 0); // Clear interrupt
}
}
int main(void)
{
char key;
unsigned int col_idx;
unsigned int candidate_key = 0xFF;
unsigned int stable = 0;
unsigned int last_key = 0xFF;
LPC_PINCON->PINSEL3 |= (2 << 14);
LPC_PWM1->TCR = (1 << 1);
LPC_PWM1->CTCR = 0x00;
LPC_PWM1->PR = 0;
LPC_PWM1->MR0 = 3000;
LPC_PWM1->MR4 = duty_cycle;
LPC_PWM1->MCR = (1 << 1) | (1 << 0);
LPC_PWM1->PCR = (1 << 12);
LPC_PWM1->LER = (1 << 0) | (1 << 4);
// === PIN CONFIGURATION ===
LPC_PINCON->PINSEL0 = 0x00000000; // All GPIO
LPC_PINCON->PINSEL1 = 0x00000000;
LPC_PINCON->PINSEL3 = (2 << 14); // PWM1.4 on P1.23 (optional)
LPC_PINCON->PINSEL4 = 0x00000000;
NVIC_EnableIRQ(PWM1_IRQn);
// === GPIO DIRECTION SETUP ===
// CNA: LEDs (P0.4-P0.11)
LPC_GPIO0->FIODIR |= LED_MASK;
LPC_PWM1->TCR = (1 << 0) | (1 << 3);
// CND: Keypad - Columns output, Row-0 input
LPC_GPIO0->FIODIR |= COL_MASK_P0; // Columns (output)
LPC_GPIO2->FIODIR |= COL_MASK_P2; // Columns (output)
LPC_GPIO0->FIODIR &= ~ROW0; // Row-0 (input)
printf("Press any key to change brightness...\n");
// === INITIALIZE GPIO STATES ===
LPC_GPIO0->FIOCLR = LED_MASK; // LEDs off
LPC_GPIO2->FIOSET = COL_MASK_P2; // Columns high (idle)
LPC_GPIO0->FIOSET = COL_MASK_P0; // Columns high (idle)
while (1)
// === PWM CONFIGURATION ===
LPC_PWM1->TCR = (1 << 1); // Reset PWM
LPC_PWM1->CTCR = 0; // Timer mode
LPC_PWM1->PR = 0; // No prescaler
LPC_PWM1->MR0 = 3000; // PWM period = 3000
LPC_PWM1->MR4 = duty_cycle; // Initial duty cycle = 0
LPC_PWM1->MCR = (1 << 1) | (1 << 0); // Reset and interrupt on MR0
LPC_PWM1->PCR = (1 << 12); // Enable PWM4 output
LPC_PWM1->LER = (1 << 0) | (1 << 4); // Latch MR0 and MR4
NVIC_EnableIRQ(PWM1_IRQn); // Enable PWM interrupt
LPC_PWM1->TCR = (1 << 0) | (1 << 3); // Enable counter and PWM
// === MAIN LOOP ===
while(1)
{
key = getchar();
unsigned int read_key = 0xFF;
if (key)
// Scan ROW-0 only (columns 0-3 = keys 0, 1, 2, 3)
for(col_idx = 0; col_idx < 4; col_idx++)
{
press_count++;
set_column(col_idx);
short_delay(200);
if (press_count == 1)
new_duty = 300;
else if (press_count == 2)
new_duty = 1500;
else if (press_count == 3)
new_duty = 2700;
else
{
new_duty = 0;
press_count = 0;
if(is_row0_pressed()) {
read_key = col_idx; // Key 0, 1, 2, or 3
break;
}
printf("Duty cycle set to %lu\r\n", new_duty);
delayMs(500);
}
// Restore all columns high
LPC_GPIO2->FIOSET = COL_MASK_P2;
LPC_GPIO0->FIOSET = COL_MASK_P0;
// Debounce logic
if(read_key == candidate_key) {
if(stable < 3) stable++;
} else {
candidate_key = read_key;
stable = 1;
}
// Update intensity when key is stable and changed
if(stable >= 3) {
if(candidate_key != last_key && candidate_key != 0xFF) {
last_key = candidate_key;
// Set duty cycle based on key pressed
switch(candidate_key) {
case 0: duty_cycle = 300; break; // 10% of 3000
case 1: duty_cycle = 750; break; // 25% of 3000
case 2: duty_cycle = 1500; break; // 50% of 3000
case 3: duty_cycle = 2250; break; // 75% of 3000
}
LPC_PWM1->MR4 = duty_cycle;
LPC_PWM1->LER = (1 << 4);
}
stable = 3;
}
short_delay(2000);
}
}