Create I2C.ino

Author: oclyke

libraries/Apollo3/examples/I2C/I2C.ino

@@ -0,0 +1,122 @@
+/* 
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE.md', which is part of this source code package.
+*/
+
+/*
+
+  I2C functionality is accessed via TwoWire objects or their children.
+  On the Apollo3 the MbedI2C class inherits from the TwoWire class and 
+  provides the actual implemenation based on mbed-os I2C
+  https://os.mbed.com/docs/mbed-os/v6.2/apis/i2c.html
+
+  Apollo3 features 6 IOM peripherals that can each be configured as either
+  SPI or I2C. Each IOM has only one set of pins that can be used. Check the 
+  board schematic or Apollo3 Blue datasheet to determine which IOM
+  peripherals are available on your board. There are a few different ways 
+  to access these ports:
+  - via pre-defined MbedI2C objects like Wire, Wire1 -> Wire5
+  - declaring your own MbedI2C object using pins that correspond to the correct IOM
+
+  Once you have an MbedI2C object to work with you can use all the standard 
+  Arduino SPI API methods on it
+  https://www.arduino.cc/en/reference/wire
+
+  This example will use threads to organize I2C operations based on board
+  capabilities. The test function will list I2C devices detected on each I2C port
+
+  Wiring:
+  For each applicable I2C port:
+  SCL <--> sensor SCL
+  SDA <--> sensor SDA
+  3V3 <--> sensor 3V3
+  GND <--> sensor GND
+
+*/
+ 
+#include "Wire.h"
+
+// This thread will use the pre-defined SPI object if it exists
+#if VARIANT_WIRE_INTFCS > 0
+rtos::Thread wire_thread;
+void wire_thread_fn( void ){
+  Wire.begin();
+  while(1){
+    testPortI2C(Wire);
+    delay(1000);
+  }
+}
+#endif
+
+// This thread will use the pre-defined SPI1 object if it exists
+#if VARIANT_WIRE_INTFCS > 1
+rtos::Thread wire1_thread;
+void wire1_thread_fn( void ){
+  delay(100);
+  Wire1.begin();
+  while(1){
+    testPortWire(Wire1);
+    delay(1000);
+  }
+}
+#endif
+
+// This thread will create its own MbedI2C object using IOM pins
+#define mySDA D25
+#define mySCL D27
+MbedI2C myWire(mySDA, mySCL);
+rtos::Thread mywire_thread;
+void mywire_thread_fn( void ){
+  delay(200);
+  myWire.begin();
+  while(1){
+    testPortI2C(myWire);
+    delay(1000);
+  }
+}
+
+void testPortI2C(MbedI2C &i2c){
+  Serial.printf("Scanning... (port: 0x%08X), time (ms): %d\n", (uint32_t)&i2c, millis());
+
+  uint8_t detected = 0;
+  for(uint8_t addr = 1; addr < 127; addr++ ){
+    // use endTransmission to determine if a device is present at address
+    i2c.beginTransmission(addr);
+    uint8_t retval = i2c.endTransmission();
+
+    if(retval == 0){
+      Serial.printf("\t0x%02X detected\n", addr);
+      detected++;
+    }
+  }
+
+  if(!detected){
+    Serial.printf("\tNo device detected!\n");
+  }
+
+  Serial.println();
+}
+ 
+void setup() {
+  Serial.begin(115200);
+  Serial.println("Apollo3 - I2C");
+
+  pinMode(LED_BUILTIN, OUTPUT);
+
+#if VARIANT_WIRE_INTFCS > 0
+  wire_thread.start(wire_thread_fn);
+#endif
+
+#if VARIANT_WIRE_INTFCS > 1
+  wire1_thread.start(wire1_thread_fn);
+#endif
+
+   mywire_thread.start(mywire_thread_fn);
+}
+
+void loop() {
+  digitalWrite(LED_BUILTIN, LOW);
+  delay(1000);
+  digitalWrite(LED_BUILTIN, HIGH);
+  delay(1000);
+}