Add pwm sound sample code

Code/picocalc_helloworld/CMakeLists.txt

@@ -14,7 +14,7 @@ include_directories(
 
 add_subdirectory(i2ckbd)
 add_subdirectory(lcdspi)
-
+add_subdirectory(pwm_sound)
 add_subdirectory(${CMAKE_CURRENT_LIST_DIR}/rp2040-psram rp2040-psram)
 
 add_executable(picocalc_helloworld
@@ -47,6 +47,7 @@ target_link_libraries(picocalc_helloworld
 	i2ckbd
 	lcdspi
     rp2040-psram
+	pwm_sound
 	)
 
 pico_enable_stdio_usb(picocalc_helloworld 0)

Code/picocalc_helloworld/main.c

@@ -6,10 +6,11 @@
 #include <string.h>
 #include "pico/stdlib.h"
 #include "hardware/gpio.h"
-
+#include "hardware/clocks.h"
 #include "i2ckbd.h"
 #include "lcdspi.h"
 #include "psram_spi.h"
+#include "pwm_sound.h"
 
 const uint LEDPIN = 25;
 psram_spi_inst_t* async_spi_inst;
@@ -174,9 +175,39 @@ int psram_test(psram_spi_inst_t*psram_spi){
     lcd_print_string("PSRAM testing done\n");
 }
 
+
+#include "sample.h"
+int wav_position = 0;
+
+void pwm_interrupt_handler() {
+    int slice_l = pwm_gpio_to_slice_num(AUDIO_PIN_L);
+    int slice_r = pwm_gpio_to_slice_num(AUDIO_PIN_R);
+
+    pwm_clear_irq(slice_l);
+    pwm_clear_irq(slice_r);
+
+    if (wav_position < (WAV_DATA_LENGTH << 3) - 1) {
+        pwm_set_chan_level(pwm_gpio_to_slice_num(AUDIO_PIN_L), PWM_CHAN_A, WAV_DATA[wav_position >> 3]);
+        pwm_set_chan_level(pwm_gpio_to_slice_num(AUDIO_PIN_R), PWM_CHAN_B, WAV_DATA[wav_position >> 3]);
+
+        wav_position++;
+    } else {
+        wav_position = 0; // Stop
+        pwm_set_chan_level(slice_l, PWM_CHAN_A, 0);
+        pwm_set_chan_level(slice_r, PWM_CHAN_B, 0);
+
+        pwm_set_irq_enabled(slice_l, false);
+        pwm_set_irq_enabled(slice_r, false);
+        irq_remove_handler(PWM_IRQ_WRAP, pwm_interrupt_handler);
+        //
+    }
+}
+
 int main() {
 
     stdio_init_all();
+    set_sys_clock_khz(133000, true);
+
 
     init_i2c_kbd();
     lcd_init();
@@ -190,10 +221,13 @@ int main() {
     sleep_ms(500);
     gpio_put(LEDPIN, 0);
 
-    psram_spi_inst_t psram_spi = psram_spi_init_clkdiv(pio1, -1,1.0f,true);
+    init_pwm(pwm_interrupt_handler);
 
+    psram_spi_inst_t psram_spi = psram_spi_init_clkdiv(pio1, -1,1.0f,true);
     psram_test(&psram_spi);
+
     while (1) {
+
         int c = lcd_getc(0);
         if(c != -1 && c > 0) {
             lcd_putc(0,c);

Code/picocalc_helloworld/pwm_sound/CMakeLists.txt

@@ -0,0 +1,19 @@
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+
+project(pwm_sound
+        VERSION 0.0.1
+        DESCRIPTION "pwm_sound for rp2040."
+        )
+
+add_library(pwm_sound INTERFACE)
+
+target_sources(pwm_sound INTERFACE
+        pwm_sound.c
+        )
+
+target_link_libraries(pwm_sound INTERFACE  pico_stdlib hardware_pwm)
+
+target_include_directories(pwm_sound INTERFACE ${CMAKE_CURRENT_LIST_DIR})

Code/picocalc_helloworld/pwm_sound/pwm_sound.c

@@ -0,0 +1,33 @@
+
+#include "pwm_sound.h"
+
+
+void init_pwm(irq_handler_t my_handler) {
+
+    gpio_set_function(AUDIO_PIN_L, GPIO_FUNC_PWM);
+    gpio_set_function(AUDIO_PIN_R, GPIO_FUNC_PWM);
+
+    int slice_l = pwm_gpio_to_slice_num(AUDIO_PIN_L);
+    int slice_r = pwm_gpio_to_slice_num(AUDIO_PIN_R);
+
+
+    pwm_clear_irq(slice_l);
+    pwm_clear_irq(slice_r);
+    pwm_set_irq_enabled(slice_l, true);
+    pwm_set_irq_enabled(slice_r, true);
+
+    irq_set_exclusive_handler(PWM_IRQ_WRAP, my_handler);
+    irq_set_enabled(PWM_IRQ_WRAP, true);
+
+
+    pwm_config config = pwm_get_default_config();
+    pwm_config_set_clkdiv(&config, 6.05f); // 133MHz
+    pwm_config_set_wrap(&config, 250);
+
+
+    pwm_init(slice_l, &config, true);
+    pwm_init(slice_r, &config, true);
+
+    pwm_set_chan_level(slice_l, PWM_CHAN_A, 0);
+    pwm_set_chan_level(slice_r, PWM_CHAN_B, 0);
+}

Code/picocalc_helloworld/pwm_sound/pwm_sound.h

@@ -0,0 +1,15 @@
+
+#ifndef PWM_SOUND_H
+#define PWM_SOUND_H
+
+#include "pico/stdlib.h"
+#include "hardware/pwm.h"
+#include <stdio.h>
+
+#define PWM_CLOCK_KHZ 133000
+#define AUDIO_PIN_L 26
+#define AUDIO_PIN_R 27
+
+void init_pwm(irq_handler_t);
+
+#endif //PWM_SOUND_H