now with sidetone

CMakeLists.txt

@@ -49,6 +49,7 @@ target_include_directories(pico_keyer PRIVATE
 target_link_libraries(pico_keyer 
   hardware_flash
   hardware_exception
+  hardware_pwm
   pico_flash
 )
 

src/CMakeLists.txt

@@ -2,4 +2,5 @@ target_sources(pico_keyer PRIVATE
     pico_keyer.cpp
     settings.cpp
     keyer.cpp
+    sidetone.cpp
 )

src/keyer.cpp

@@ -3,11 +3,15 @@
 #include "pico/stdlib.h"
 
 #include "keyer.h"
+#include "sidetone.h"
 
 extern const uint LED_PIN;
 extern const uint LEFT_PADDLE_PIN;
 extern const uint RIGHT_PADDLE_PIN;
 
+
+const uint SIDETONE_FREQ = 622;
+
 bool left_paddle_pressed()
 {
     if (!gpio_get(LEFT_PADDLE_PIN))
@@ -68,6 +72,7 @@ void Keyer::run()
             m_currentlyKeying = true;
             m_keying_until = make_timeout_time_us(m_elementDuration);
             gpio_put(LED_PIN, 1);
+            m_Sidetone.on(SIDETONE_FREQ);
             m_lastSymbolWas = Symbol::Dit;
         }
         else
@@ -76,6 +81,7 @@ void Keyer::run()
             {
                 m_currentlyKeying = false;
                 gpio_put(LED_PIN, 0);
+                m_Sidetone.off();
                 m_previousState = State::Dit;
                 state = State::InterCharSpace;
             }
@@ -87,6 +93,7 @@ void Keyer::run()
             m_currentlyKeying = true;
             m_keying_until = make_timeout_time_us(m_elementDuration * 3);
             gpio_put(LED_PIN, 1);
+            m_Sidetone.on(SIDETONE_FREQ);
             m_lastSymbolWas = Symbol::Dah;
         }
         else
@@ -95,6 +102,7 @@ void Keyer::run()
             {
                 m_currentlyKeying = false;
                 gpio_put(LED_PIN, 0);
+                m_Sidetone.off();
                 m_previousState = State::Dah;
                 state = State::InterCharSpace;
             }

src/keyer.h

@@ -1,6 +1,10 @@
 #ifndef KEYER_H
 #define KEYER_H
 
+#include "sidetone.h"
+
+extern const uint BUZZER_PIN;
+
 class Keyer final
 {
 public:
@@ -31,6 +35,7 @@ private:
     absolute_time_t m_keying_until{0};
     absolute_time_t m_pausing_until{0};
     Symbol m_lastSymbolWas{Symbol::Dit};
+    Sidetone m_Sidetone{BUZZER_PIN};
 };
 
 #endif

src/pico_keyer.cpp

@@ -14,6 +14,7 @@ namespace
 extern const uint LED_PIN = PICO_DEFAULT_LED_PIN;
 extern const uint LEFT_PADDLE_PIN = 14;
 extern const uint RIGHT_PADDLE_PIN = 15;
+extern const uint BUZZER_PIN = 13;
 
 void setup()
 {
@@ -29,6 +30,7 @@ void setup()
     gpio_init(RIGHT_PADDLE_PIN);
     gpio_set_dir(RIGHT_PADDLE_PIN, GPIO_IN);
     gpio_pull_up(RIGHT_PADDLE_PIN);
+
     sleep_ms(1000);
 }
 
@@ -45,7 +47,7 @@ int main()
     // printf("Element duration (u_sec): %" PRIu64 "\n", element_duration_us(settings.wpm));
     printf("\n");
 
-    Keyer keyer(15);
+    Keyer keyer(25);
 
     while (true)
     {

src/sidetone.cpp

@@ -0,0 +1,29 @@
+#include "pico/stdlib.h"
+#include "hardware/pwm.h"
+
+#include "sidetone.h"
+
+Sidetone::Sidetone(uint gpio) : m_gpio(gpio)
+{
+    gpio_set_function(gpio, GPIO_FUNC_PWM);
+    uint slice_num = pwm_gpio_to_slice_num(gpio);
+    pwm_config config = pwm_get_default_config();
+    pwm_init(slice_num, &config, true);
+}
+
+void Sidetone::on(uint freq)
+{
+    // Calculate and cofigure new clock divider according to the frequency
+    // This formula is assuming we are running at 125MHz.
+    // TODO: Make this work for any frequency
+    float clkdiv = (1.f / freq) * 2000.f;
+    uint slice_num = pwm_gpio_to_slice_num(m_gpio);
+    pwm_set_clkdiv(slice_num, clkdiv);
+    // Configure duty to 50% ((2**16)-1)/2) to generate a square wave
+    pwm_set_gpio_level(m_gpio, 32768U);
+}
+
+void Sidetone::off()
+{
+    pwm_set_gpio_level(m_gpio, 0);
+}

src/sidetone.h

@@ -0,0 +1,16 @@
+#ifndef SIDETONE_H
+#define SIDETONE_H
+
+class Sidetone
+{
+public:
+    Sidetone(uint gpio);
+    void on(uint freq);
+    void off();
+
+private:
+    Sidetone(){};
+    uint m_gpio{0};
+};
+
+#endif