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PWM Disp

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This commit is contained in:
sherlock 2025-10-23 12:56:40 +05:30
parent 023708f6d0
commit e36e851593
1 changed files with 52 additions and 63 deletions
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115
ES/Lab/Lab11/PWM_Keyboard.c
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@ -1,8 +1,8 @@
#include "LPC17xx.h"
// PWM variables
unsigned long int duty_cycle = 0;
unsigned long int pwm_counter = 0;
volatile unsigned long int duty_cycle = 10; // Start at 10%
volatile unsigned long int pwm_counter = 0;
// Pin definitions
#define LED_SHIFT 4 // CNA: P0.4-P0.11
@ -18,10 +18,12 @@ unsigned long int pwm_counter = 0;
#define COL_MASK_P0 (COL2 | COL3)
#define COL_MASK_P2 (COL0 | COL1)
#define PWM_PERIOD 100 // Smaller for faster PWM
#define PWM_PERIOD 100 // 100 steps for percentage
static void short_delay(volatile unsigned int d) {
while(d--) __NOP();
static void delay_ms(unsigned int ms) {
unsigned int i, j;
for(i = 0; i < ms; i++)
for(j = 0; j < 10000; j++);
}
static void set_column(unsigned int col)
@ -42,12 +44,12 @@ static unsigned int is_row0_pressed(void)
return !(LPC_GPIO0->FIOPIN & ROW0);
}
// PWM Interrupt Handler - Software PWM
// HIGH-SPEED PWM Interrupt Handler
void PWM1_IRQHandler(void)
{
if (LPC_PWM1->IR & (1 << 0))
{
// Software PWM for all 8 LEDs
// Fast software PWM for all 8 LEDs
if(pwm_counter < duty_cycle)
LPC_GPIO0->FIOSET = LED_MASK; // All LEDs ON
else
@ -57,72 +59,71 @@ void PWM1_IRQHandler(void)
if(pwm_counter >= PWM_PERIOD)
pwm_counter = 0;
LPC_PWM1->IR = (1 << 0); // Clear interrupt
LPC_PWM1->IR = (1 << 0); // Clear interrupt flag
}
}
int main(void)
{
unsigned int col_idx;
unsigned int candidate_key = 0xFF;
unsigned int stable = 0;
unsigned int read_key;
unsigned int last_key = 0xFF;
// === SYSTEM CLOCK SETUP (Optional but recommended) ===
SystemInit(); // Use default clock setup
// === PIN CONFIGURATION ===
LPC_PINCON->PINSEL0 &= ~(0xFFFF << 8); // Clear P0.4-P0.11 (GPIO)
LPC_PINCON->PINSEL1 &= ~(0xFFFF << 14); // Clear P0.23-P0.28
LPC_PINCON->PINSEL3 &= ~(0x3 << 14); // Clear P1.23
LPC_PINCON->PINSEL4 &= ~(0xF << 0); // Clear P2.0-P2.1
LPC_PINCON->PINSEL0 &= ~(0xFFFF << 8); // P0.4-P0.11 as GPIO
LPC_PINCON->PINSEL1 &= ~(0xFFFF << 14); // P0.23-P0.28 as GPIO
LPC_PINCON->PINSEL4 &= ~(0xF << 0); // P2.0-P2.1 as GPIO
// === GPIO DIRECTION SETUP ===
LPC_GPIO0->FIODIR |= LED_MASK; // P0.4-P0.11: LEDs (output)
LPC_GPIO0->FIODIR |= COL_MASK_P0; // Keypad columns (output)
LPC_GPIO2->FIODIR |= COL_MASK_P2; // Keypad columns (output)
LPC_GPIO0->FIODIR &= ~ROW0; // Row-0 (input)
// === GPIO SETUP ===
LPC_GPIO0->FIODIR |= LED_MASK; // LEDs output
LPC_GPIO0->FIODIR |= COL_MASK_P0; // Columns output
LPC_GPIO2->FIODIR |= COL_MASK_P2; // Columns output
LPC_GPIO0->FIODIR &= ~ROW0; // Row input
// === INITIALIZE GPIO ===
LPC_GPIO0->FIOCLR = LED_MASK; // All LEDs off initially
LPC_GPIO2->FIOSET = COL_MASK_P2; // Columns high
LPC_GPIO0->FIOSET = COL_MASK_P0; // Columns high
// Initialize
LPC_GPIO0->FIOCLR = LED_MASK;
LPC_GPIO2->FIOSET = COL_MASK_P2;
LPC_GPIO0->FIOSET = COL_MASK_P0;
// === PWM CONFIGURATION ===
// === HIGH-SPEED PWM CONFIGURATION ===
LPC_SC->PCONP |= (1 << 6); // Power on PWM1
LPC_PWM1->TCR = (1 << 1); // Reset PWM
LPC_PWM1->TCR = (1 << 1); // Reset
LPC_PWM1->CTCR = 0; // Timer mode
LPC_PWM1->PR = 99; // Prescaler: divide by 100
// Creates ~10kHz interrupt rate
LPC_PWM1->PR = 9; // Prescaler = 10
// 100MHz / 10 = 10MHz timer clock
LPC_PWM1->MR0 = PWM_PERIOD; // PWM period = 100
LPC_PWM1->MR4 = 0; // Duty cycle = 0
LPC_PWM1->MR0 = 100; // Match every 100 ticks
// Interrupt rate = 10MHz/100 = 100kHz
// PWM frequency = 100kHz/100 = 1kHz
// NO VISIBLE FLICKER!
LPC_PWM1->MCR = (1 << 1) | (1 << 0); // Reset on MR0, interrupt enabled
LPC_PWM1->MCR = (1 << 1) | (1 << 0); // Reset on MR0 + interrupt
LPC_PWM1->LER = (1 << 0); // Latch MR0
NVIC_EnableIRQ(PWM1_IRQn); // Enable PWM interrupt
NVIC_EnableIRQ(PWM1_IRQn); // Enable interrupt
NVIC_SetPriority(PWM1_IRQn, 0); // Highest priority
LPC_PWM1->TCR = (1 << 0) | (1 << 3); // Enable PWM and counter
// Initial duty cycle: 10%
duty_cycle = 10;
LPC_PWM1->TCR = (1 << 0) | (1 << 3); // Start PWM
// === MAIN LOOP ===
while(1)
{
unsigned int read_key = 0xFF;
read_key = 0xFF;
// Scan ROW-0 (keys 0, 1, 2, 3)
// Scan ROW-0 only
for(col_idx = 0; col_idx < 4; col_idx++)
{
set_column(col_idx);
short_delay(500);
delay_ms(5); // Short delay for stable reading
if(is_row0_pressed()) {
read_key = col_idx;
read_key = col_idx; // Key 0, 1, 2, or 3
// Wait for key release
while(is_row0_pressed()) {
delay_ms(10);
}
break;
}
}
@ -131,30 +132,18 @@ int main(void)
LPC_GPIO2->FIOSET = COL_MASK_P2;
LPC_GPIO0->FIOSET = COL_MASK_P0;
// Debounce
if(read_key == candidate_key) {
if(stable < 5) stable++;
} else {
candidate_key = read_key;
stable = 1;
}
// Update brightness immediately on key press
if(read_key != 0xFF && read_key != last_key) {
last_key = read_key;
// Update intensity when stable
if(stable >= 5) {
if(candidate_key != last_key && candidate_key != 0xFF) {
last_key = candidate_key;
// Set duty cycle (out of 100)
switch(candidate_key) {
case 0: duty_cycle = 10; break; // 10%
case 1: duty_cycle = 25; break; // 25%
case 2: duty_cycle = 50; break; // 50%
case 3: duty_cycle = 75; break; // 75%
}
switch(read_key) {
case 0: duty_cycle = 10; break; // 10%
case 1: duty_cycle = 25; break; // 25%
case 2: duty_cycle = 50; break; // 50%
case 3: duty_cycle = 75; break; // 75%
}
stable = 5;
}
short_delay(5000);
delay_ms(50); // Main loop delay
}
}