Feature: Add hardware PWM support

Makefile

@@ -60,6 +60,7 @@ per/spi \
 per/spiMultislave \
 per/tim \
 per/uart \
+per/pwm \
 ui/UI \
 ui/AbstractMenu \
 ui/FullScreenItemMenu \

examples/PWM_Output/CMakeLists.txt

@@ -0,0 +1,3 @@
+set(FIRMWARE_NAME PWM_Output)
+set(FIRMWARE_SOURCES PWM_Output.cpp)
+include(DaisyProject)

examples/PWM_Output/Makefile

@@ -0,0 +1,12 @@
+# Project Name
+TARGET = PWM_Output
+
+# Sources
+CPP_SOURCES = PWM_Output.cpp
+
+# Library Locations
+LIBDAISY_DIR = ../..
+
+# Core location, and generic Makefile.
+SYSTEM_FILES_DIR = $(LIBDAISY_DIR)/core
+include $(SYSTEM_FILES_DIR)/Makefile

examples/PWM_Output/PWM_Output.cpp

@@ -0,0 +1,86 @@
+// Hardware PWM demo
+//
+// Demonstrates how to use a PWMHandle to output hardware-generated PWM.
+// No special setup is required, as the built-in LED on the Seed is used for display.
+//
+#include "daisy_seed.h"
+#include <cmath>
+
+using namespace daisy;
+using namespace daisy::seed;
+
+DaisySeed hw;
+
+const float TWO_PI = 6.2831853072f;
+
+int main(void)
+{
+    // Initialize the Daisy Seed hardware
+    hw.Init();
+    hw.StartLog(false);
+
+    // First, we'll create a PWMHandle that enables PWM mode on a given timer. Each handle provides up to 4 output channels.
+    PWMHandle pwm_tim3;
+
+    {
+        // Configure the PWM peripheral
+        PWMHandle::Config pwm_config;
+        // We'll use TIM3 for PWM output.
+        pwm_config.periph = PWMHandle::Config::Peripheral::TIM_3;
+        // TIM3 is a 16-bit timer, so the max period is 0xffff. We'll use 0xff to give a higher-frequency PWM signal at the expense of lower precision.
+        pwm_config.period = 0xff;
+
+        // Initialize
+        if(pwm_tim3.Init(pwm_config) != PWMHandle::Result::OK)
+        {
+            hw.PrintLine("Could not initialize PWM handle");
+        }
+
+        // You can also create the config inline when initializing:
+        // pwm_tim3.Init({PWMHandle::Config::Peripheral::TIM_3});
+    }
+
+    {
+        // Next, configure an individual channel. We'll use Channel 2, which can connect to the Seed's internal LED
+        PWMHandle::Channel::Config channel_config;
+        // Each timer and channel supports a different set of pins. If no pin is selected, the default for that channel will be selected.
+        channel_config.pin = {PORTC, 7};
+        // Polarity can be changed for individual channels
+        channel_config.polarity = PWMHandle::Channel::Config::Polarity::HIGH;
+
+        // Initialize
+        if(pwm_tim3.Channel2().Init(channel_config) != PWMHandle::Result::OK)
+        {
+            hw.PrintLine("Could not initialize PWM channel");
+        }
+
+        // Like before, you can also create the config inline, or leave it blank to use defaults.
+        // pwm_tim3.Channel2().Init();
+
+        // Each PWMHandle supports up to 4 channels at once.
+    }
+
+    // Instead of calling pwm_tim3.Channel2() every time, you can also store a reference. Note that this reference is valid even if taken before initialization,
+    // but it must be initialized after the PWMHandle and before calling Set().
+    auto& led_pwm = pwm_tim3.Channel2();
+
+    float phase = 0.0f;
+    while(1)
+    {
+        // Generate a 1 Hz pulse
+        float brightness = std::cos(TWO_PI * phase) * 0.5f + 0.5f;
+
+        // Set the PWM channel duty cycle. We also apply a cubic gamma correction factor here to linearize the LED's brightness
+        // When calling this method with a float, the value is normalized to [0, period]
+        led_pwm.Set(brightness * brightness * brightness);
+
+        // You can also call SetRaw to directly set the duty cycle.
+        // led_pwm.SetRaw(0x7f);
+
+        phase += 0.01f;
+        if(phase > 1.0f)
+            phase -= 1.0f;
+
+        hw.DelayMs(10);
+    }
+}

src/daisy.h

@@ -10,6 +10,7 @@
 #include "per/dac.h"
 #include "per/gpio.h"
 #include "per/tim.h"
+#include "per/pwm.h"
 #include "dev/leddriver.h"
 #include "dev/mpr121.h"
 #include "dev/sdram.h"