Daniel Knox
A simple I2C library for ESCs using the Blue Robotics version of SimonK's TGY firmware (https://github.com/bluerobotics/tgy). This library supports the BlueESC, but also the Afro Nfet 30A. I2C is an alternative interface for micro-controllers, rather than using PWM (as a servo) -- this provides some additional features like temperature level, RPM, etc.
Dependents: SimonK_I2C_ESC_Example
Example program here:
Import programSimonK_I2C_ESC_Example
Simple example for the SimonK_I2C_ESC. Tested on the FRDM K64F.
Last commit 01 Apr 2016 by 
Daniel Knox
Additional guidance is provided in the Wiki
Diff: SimonK_I2C_ESC.cpp
- Revision:
- 0:41ddae212f64
- Child:
- 1:7efb04a9c0dd
diff -r 000000000000 -r 41ddae212f64 SimonK_I2C_ESC.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/SimonK_I2C_ESC.cpp Fri Apr 01 06:45:10 2016 +0000
@@ -0,0 +1,77 @@
+#include "SimonK_I2C_ESC.h"
+
+namespace {
+ char _buffer[9];
+}
+
+SimonK_I2C_ESC::SimonK_I2C_ESC(I2C &i2c, char address, char poleCount) : _i2c(i2c){
+ _address = address;
+ _poleCount = poleCount;
+ // A timer is needed to calculate the RPM.
+ mbed_rpm_timer.start();
+ _rpmTimer = mbed_rpm_timer.read_ms();
+}
+
+// Read the incoming data buffer from an ESC
+void SimonK_I2C_ESC::readBuffer(char buffer[]) {
+ char readStartAddress = 0x02;
+ _i2c.write(_address,&readStartAddress,1,false);
+ _i2c.read(_address,buffer,9);
+}
+
+// Send motor speed command to ESC
+void SimonK_I2C_ESC::set(short throttle) {
+ char throttleData[3];
+ throttleData[0] = 0x00; // Throttle Start Address
+ throttleData[1] = throttle>>8;
+ throttleData[2] = throttle;
+ _i2c.write(_address, throttleData, 3, true);
+}
+
+// Send motor speed command to ESC
+void SimonK_I2C_ESC::setPWM(short pwm) {
+ set((pwm - 1100) * (32767 - -32767) / (1900 - 1100) + -32767);
+}
+
+void SimonK_I2C_ESC::update() {
+ _buffer[8] = 0x00; // Reset last byte so we can check for alive
+ readBuffer(_buffer);
+ _rpm = (_buffer[0] << 8) | _buffer[1];
+ _voltage_raw = (_buffer[2] << 8) | _buffer[3];
+ _temp_raw = (_buffer[4] << 8) | _buffer[5];
+ _current_raw = (_buffer[6] << 8) | _buffer[7];
+ _identifier = _buffer[8];
+ _rpm = float(_rpm) / (( mbed_rpm_timer.read_ms() -_rpmTimer)/1000.0f)*60/ float(_poleCount);
+ _rpmTimer = mbed_rpm_timer.read_ms();
+}
+
+bool SimonK_I2C_ESC::isAlive() {
+ return (_identifier == 0xab);
+}
+
+float SimonK_I2C_ESC::voltage() {
+ return float(_voltage_raw)/65536.0f*5.0f*6.45f;
+}
+
+float SimonK_I2C_ESC::current() {
+ return (float(_current_raw)-32767)/65535.0f*5.0f*14.706f;
+}
+
+float SimonK_I2C_ESC::temperature() {
+ // This code was taken from an Adafruit
+ float resistance = SERIESRESISTOR/(65535/float(_temp_raw)-1);
+
+ float steinhart;
+ steinhart = resistance / THERMISTORNOMINAL; // (R/Ro)
+ steinhart = log(steinhart); // ln(R/Ro)
+ steinhart /= BCOEFFICIENT; // 1/B * ln(R/Ro)
+ steinhart += float(1.0) / (TEMPERATURENOMINAL + 273.15); // + (1/To)
+ steinhart = float (1.0) / steinhart; // Invert
+ steinhart -= float(273.15); // convert to C
+
+ return steinhart;
+}
+
+short SimonK_I2C_ESC::rpm() {
+ return _rpm;
+}
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