initial working proof-of-concept of rp2040 support

examples/RP2040ClockBlink/RP2040ClockBlink.ino

@@ -0,0 +1,92 @@
+/* USB MIDI Sync Box - RP2040 example that just blinks LED
+ *  
+ * 
+ * This example code is in the public domain.
+ * 
+ */
+
+//#define LED_BUILTIN PIN_LED_B
+
+#include "Adafruit_TinyUSB.h"
+
+#include <uClock.h>
+
+uint8_t bpm_blink_timer = 1;
+void handle_bpm_led(uint32_t tick)
+{
+  // BPM led indicator
+  if ( !(tick % (96)) || (tick == 1) ) {  // first compass step will flash longer
+    bpm_blink_timer = 8;
+    digitalWrite(LED_BUILTIN, LOW);
+  } else if ( !(tick % (24)) ) {   // each quarter led on
+    bpm_blink_timer = 1;
+    digitalWrite(LED_BUILTIN, LOW);
+  } else if ( !(tick % bpm_blink_timer) ) { // get led off
+    digitalWrite(LED_BUILTIN, HIGH);
+  }
+}
+
+
+// Internal clock handlers
+void onSync24Callback(uint32_t tick) {
+  handle_bpm_led(tick);
+}
+
+void onClockStart() {
+  //MIDI_USB.sendRealTime(midi::Start);
+}
+
+void onClockStop() {
+  //MIDI_USB.sendRealTime(midi::Stop);
+}
+
+void setup() {
+/*#if defined(ARDUINO_ARCH_MBED) && defined(ARDUINO_ARCH_RP2040)
+  // Manual begin() is required on core without built-in support for TinyUSB such as mbed rp2040
+  TinyUSB_Device_Init(0);
+#endif*/
+
+  //MIDI_USB.begin(MIDI_CHANNEL_OMNI);
+
+  // A led to count bpms
+  pinMode(LED_BUILTIN, OUTPUT);
+  digitalWrite(LED_BUILTIN, HIGH);
+  delay(500);
+  digitalWrite(LED_BUILTIN, LOW);
+  delay(500);
+  digitalWrite(LED_BUILTIN, HIGH);
+  delay(500);
+  digitalWrite(LED_BUILTIN, LOW);
+  delay(500);
+
+  
+  Serial.begin(115200);
+  /*while (!Serial)
+    delay(1);*/
+
+    // Setup our clock system
+
+  // Inits the clock
+  uClock.init();
+  // Set the callback function for the clock output to send MIDI Sync message.
+  uClock.setOnSync24(onSync24Callback);
+  // Set the callback function for MIDI Start and Stop messages.
+  uClock.setOnClockStart(onClockStart);  
+  uClock.setOnClockStop(onClockStop);
+  // Set the clock BPM to 126 BPM
+  uClock.setTempo(60);
+  // Starts the clock, tick-tac-tick-tac..
+  //Serial.println("about to uClock.start()..."); Serial.flush();
+  uClock.start();
+  //Serial.println("uClock.start()ed!"); Serial.flush();
+}
+
+uint32_t count = 0;
+
+// Do it whatever to interface with Clock.stop(), Clock.start(), Clock.setTempo() and integrate your environment...
+void loop() {
+  //MIDI_USB.read();
+  //count++;
+  //if (millis()%1000==0)
+  //  Serial.println("looped!");
+}

examples/RP2040UsbMasterMidiClock/RP2040UsbMasterMidiClock.ino

@@ -0,0 +1,96 @@
+/* USB MIDI Sync Box - example that also prints to serial and sends USB midi as well as blinking LED
+ * (usb part still needs testing to make sure it works!)
+ *  
+ * This example code is in the public domain.
+ * 
+ */
+#include <Adafruit_TinyUSB.h>
+#include <MIDI.h>
+
+Adafruit_USBD_MIDI usb_midi;
+MIDI_CREATE_INSTANCE(Adafruit_USBD_MIDI, usb_midi, MIDI_USB);
+
+//#define LED_BUILTIN PIN_LED_B
+
+//MIDI_CREATE_INSTANCE(HardwareSerial, Serial1, MIDI);
+#include <uClock.h>
+
+uint8_t bpm_blink_timer = 1;
+void handle_bpm_led(uint32_t tick)
+{
+  // BPM led indicator
+  if ( !(tick % (96)) || (tick == 1) ) {  // first compass step will flash longer
+    bpm_blink_timer = 8;
+    digitalWrite(LED_BUILTIN, LOW);
+  } else if ( !(tick % (24)) ) {   // each quarter led on
+    bpm_blink_timer = 1;
+    digitalWrite(LED_BUILTIN, LOW);
+  } else if ( !(tick % bpm_blink_timer) ) { // get led off
+    digitalWrite(LED_BUILTIN, HIGH);
+  }
+}
+
+
+// Internal clock handlers
+void onSync24Callback(uint32_t tick) {
+  // Send MIDI_CLOCK to external gears
+  MIDI_USB.sendRealTime(midi::Clock);
+  handle_bpm_led(tick);
+}
+
+void onClockStart() {
+  MIDI_USB.sendRealTime(midi::Start);
+}
+
+void onClockStop() {
+  MIDI_USB.sendRealTime(midi::Stop);
+}
+
+void setup() {
+#if defined(ARDUINO_ARCH_MBED) && defined(ARDUINO_ARCH_RP2040)
+  // Manual begin() is required on core without built-in support for TinyUSB such as mbed rp2040
+  TinyUSB_Device_Init(0);
+#endif
+
+  MIDI_USB.begin(MIDI_CHANNEL_OMNI);
+
+  // A led to count bpms
+  pinMode(LED_BUILTIN, OUTPUT);
+  
+  Serial.begin(115200);
+  while (!Serial)
+    delay(1);
+  
+  // wait until device mounted
+  /*while( !TinyUSBDevice.mounted() ) {
+    Serial.println("waiting for usb..");
+    Serial.flush();
+    delay(1);
+  }*/
+
+  // Setup our clock system
+  // Inits the clock
+  Serial.println("about to uClock.init()..."); Serial.flush();
+  uClock.init();
+  // Set the callback function for the clock output to send MIDI Sync message.
+  uClock.setOnSync24(onSync24Callback);
+  // Set the callback function for MIDI Start and Stop messages.
+  uClock.setOnClockStart(onClockStart);  
+  uClock.setOnClockStop(onClockStop);
+  // Set the clock BPM to 126 BPM
+  uClock.setTempo(126);
+  // Starts the clock, tick-tac-tick-tac..
+  Serial.println("about to uClock.start()..."); Serial.flush();
+  uClock.start();
+  Serial.println("uClock.start()ed!"); Serial.flush();
+}
+
+uint32_t count = 0;
+
+// Do it whatever to interface with Clock.stop(), Clock.start(), Clock.setTempo() and integrate your environment...
+void loop() {
+  MIDI_USB.read();
+  count++;
+  if (millis()%1000==0)
+    Serial.println("looped!!!");
+}

src/platforms/esp32.h

@@ -2,6 +2,7 @@
 #include <freertos/task.h>
 #include <freertos/semphr.h>
 
+// esp32-specific timer
 #define TIMER_ID	0
 hw_timer_t * _uclockTimer = NULL;
 // mutex control for ISR

src/platforms/rp2040.h

@@ -0,0 +1,57 @@
+#include <Arduino.h>
+#include "FreeRTOS.h"
+#include <task.h>
+#include <semphr.h>
+#include "pico/sync.h"
+
+// RPi-specific timer
+struct repeating_timer timer;
+
+// FreeRTOS main clock task size in bytes
+#define CLOCK_STACK_SIZE    5*1024 // adjust for your needs, a sequencer with heavy serial handling should be large in size
+TaskHandle_t taskHandle;
+// mutex to protect the shared resource
+SemaphoreHandle_t _mutex;
+// mutex control for task
+#define ATOMIC(X) xSemaphoreTake(_mutex, portMAX_DELAY); X; xSemaphoreGive(_mutex);
+
+// forward declaration of uClockHandler
+void uClockHandler();
+
+// ISR handler -- called when tick happens
+bool handlerISR(repeating_timer *timer)
+{
+    BaseType_t xHigherPriorityTaskWoken = pdFALSE;
+    // Send a notification to task1
+    vTaskNotifyGiveFromISR(taskHandle, &xHigherPriorityTaskWoken);
+    portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
+
+    return true;
+}
+
+// task for user clock process
+void clockTask(void *pvParameters)
+{
+    while (1) {
+        // wait for a notification from ISR
+        ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
+        uClockHandler();
+    }
+}
+
+void initTimer(uint32_t init_clock)
+{
+    // initialize the mutex for shared resource access
+    _mutex = xSemaphoreCreateMutex();
+
+    // create the clockTask
+    xTaskCreate(clockTask, "clockTask", CLOCK_STACK_SIZE, NULL, 1, &taskHandle);
+
+    // set up RPi interrupt timer
+    add_repeating_timer_us(init_clock, &handlerISR, NULL, &timer);
+}
+
+void setTimer(uint32_t us_interval) {
+    cancel_repeating_timer(&timer);
+	add_repeating_timer_us(us_interval, &handlerISR, NULL, &timer);
+}

src/uClock.cpp

@@ -57,6 +57,12 @@
 #if defined(ARDUINO_ARCH_STM32)
     #include "platforms/stm32.h"
 #endif
+//
+// RP2040 (Raspberry Pico) family
+//
+#if defined(ARDUINO_ARCH_RP2040)
+    #include "platforms/rp2040.h"
+#endif
 
 //
 // Platform specific timer setup/control