Changed channels and lostFrames to uint16_t data types to more accura…

…tely match the data type being used. Modified the scale and bias for the readCal() function to be single precision floats instead of doubles. Changed the example and README to match the code changes.
dannysilence · Sep 21, 2016 · 56325b3 · 56325b3
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Showing 4 changed files with 25 additions and 25 deletions.
diff --git a/README.md b/README.md
@@ -47,39 +47,39 @@ This should be called in your setup function. It initializes the serial communic
 x8r.begin();
 ```
 
-**bool read(int16_t* channels, uint8_t* failsafe, int* lostFrames)**
-*read(int16_t&ast; channels, uint8_t&ast; failsafe, int&ast; lostFrames)* reads data from the SBUS receiver and parses the SBUS packet. When a complete packet is received, *read(int16_t&ast; channels, uint8_t&ast; failsafe, int&ast; lostFrames)* returns *true* and the *channels[0-15]*, *failsafe*, and *lost frames* data is available. Note that *lost frames* is a counter that increments once each time a lost frame flag is read in the SBUS packet. For example, placing the following code in the loop function will print the value of *channel 0* every time a valid SBUS packet is received.
+**bool read(uint16_t* channels, uint8_t* failsafe, uint16_t* lostFrames)**
+*read(uint16_t&ast; channels, uint8_t&ast; failsafe, uint16_t&ast; lostFrames)* reads data from the SBUS receiver and parses the SBUS packet. When a complete packet is received, *read(uint16_t&ast; channels, uint8_t&ast; failsafe, uint16_t&ast; lostFrames)* returns *true* and the *channels[0-15]*, *failsafe*, and *lost frames* data is available. Note that *lost frames* is a counter that increments once each time a lost frame flag is read in the SBUS packet. For example, placing the following code in the loop function will print the value of *channel 0* every time a valid SBUS packet is received.
 
 ```C++
-int16_t channels[16];
+uint16_t channels[16];
 uint8_t failSafe;
-int lostFrames = 0;
+uint16_t lostFrames = 0;
 
 if(x8r.read(&channels[0], &failSafe, &lostFrames)){
 	Serial.println(channels[0]);
 }
 ```
 
-**bool readCal(float* calChannels, uint8_t* failsafe, int* lostFrames)**
-*readCal(float&ast; calChannels, uint8_t&ast; failsafe, int&ast; lostFrames)* reads data from the SBUS receiver and parses the SBUS packet. The data from *channels[0-15]* is calibrated to a +/- 1.0 float value assuming a linear relationship based on the minimum and maximum value (172 and 1811 using FrSky set to 0-100%). When a complete packet is received, *readCal(float&ast; calChannels, uint8_t&ast; failsafe, int&ast; lostFrames)* returns *true* and the *calChannels[0-15]*, *failsafe*, and *lost frames* data is available. Note that *lost frames* is a counter that increments once each time a lost frame flag is read in the SBUS packet. For example, placing the following code in the loop function will print the calibrated value of *channel 0* every time a valid SBUS packet is received.
+**bool readCal(float* calChannels, uint8_t* failsafe, uint16_t* lostFrames)**
+*readCal(float&ast; calChannels, uint8_t&ast; failsafe, uint16_t&ast; lostFrames)* reads data from the SBUS receiver and parses the SBUS packet. The data from *channels[0-15]* is calibrated to a +/- 1.0 float value assuming a linear relationship based on the minimum and maximum value (172 and 1811 using FrSky set to 0-100%). When a complete packet is received, *readCal(float&ast; calChannels, uint8_t&ast; failsafe, uint16_t&ast; lostFrames)* returns *true* and the *calChannels[0-15]*, *failsafe*, and *lost frames* data is available. Note that *lost frames* is a counter that increments once each time a lost frame flag is read in the SBUS packet. For example, placing the following code in the loop function will print the calibrated value of *channel 0* every time a valid SBUS packet is received.
 
 ```C++
 float channels[16];
 uint8_t failSafe;
-int lostFrames = 0;
+uint16_t lostFrames = 0;
 
 if(x8r.readCal(&channels[0], &failSafe, &lostFrames)){
 	Serial.println(channels[0]);
 }
 ```
 
-**void write(int16_t* channels)**
-*write(int16_t&ast; channels)* writes the SBUS packet to SBUS capable servos given position commands from *channels[0-15]*. Note that this function simply creates and sends the SBUS packet, but does not handle timing (i.e. the time between sending subsequent SBUS packets). This timing must be handled by the calling function. For example, placing the following code in the loop function will create and send the SBUS packet to servos every time a valid SBUS packet is received.
+**void write(uint16_t* channels)**
+*write(uint16_t&ast; channels)* writes the SBUS packet to SBUS capable servos given position commands from *channels[0-15]*. Note that this function simply creates and sends the SBUS packet, but does not handle timing (i.e. the time between sending subsequent SBUS packets). This timing must be handled by the calling function. For example, placing the following code in the loop function will create and send the SBUS packet to servos every time a valid SBUS packet is received.
 
 ```C++
-int16_t channels[16];
+uint16_t channels[16];
 uint8_t failSafe;
-int lostFrames = 0;
+uint16_t lostFrames = 0;
 
 // look for a good SBUS packet from the receiver
 if(x8r.read(&channels[0], &failSafe, &lostFrames)){

diff --git a/SBUS.cpp b/SBUS.cpp
@@ -2,7 +2,7 @@
 SBUS.cpp
 Brian R Taylor
 [email protected]
-2016-09-19
+2016-09-21
 
 Copyright (c) 2016 Bolder Flight Systems
 
@@ -72,8 +72,8 @@ void SBUS::begin(){
 }
 
 /* read the SBUS data and calibrate it to +/- 1 */
-bool SBUS::readCal(float* calChannels, uint8_t* failsafe, int* lostFrames){
-	int16_t channels[16];
+bool SBUS::readCal(float* calChannels, uint8_t* failsafe, uint16_t* lostFrames){
+	uint16_t channels[16];
 
 	// read the SBUS data
 	if(read(&channels[0],failsafe,lostFrames)){
@@ -94,7 +94,7 @@ bool SBUS::readCal(float* calChannels, uint8_t* failsafe, int* lostFrames){
 }
 
 /* read the SBUS data */
-bool SBUS::read(int16_t* channels, uint8_t* failsafe, int* lostFrames){
+bool SBUS::read(uint16_t* channels, uint8_t* failsafe, uint16_t* lostFrames){
 
   	// parse the SBUS packet
   	if(parse()){
@@ -182,7 +182,7 @@ bool SBUS::parse(){
 }
 
 /* write SBUS packets */
-void SBUS::write(int16_t* channels){
+void SBUS::write(uint16_t* channels){
 	uint8_t packet[25];
 
 	/* assemble the SBUS packet */

diff --git a/SBUS.h b/SBUS.h
@@ -2,7 +2,7 @@
 SBUS.h
 Brian R Taylor
 [email protected]
-2016-09-02
+2016-09-21
 
 Copyright (c) 2016 Bolder Flight Systems
 
@@ -31,14 +31,14 @@ class SBUS{
 	public:
     	SBUS(int bus);
     	void begin();
-    	bool read(int16_t* channels, uint8_t* failsafe, int* lostFrames);
-    	bool readCal(float* calChannels, uint8_t* failsafe, int* lostFrames);
-    	void write(int16_t* channels);
+    	bool read(uint16_t* channels, uint8_t* failsafe, uint16_t* lostFrames);
+    	bool readCal(float* calChannels, uint8_t* failsafe, uint16_t* lostFrames);
+    	void write(uint16_t* channels);
   	private:
   		int _bus;
   		int _fpos;
-  		const double _sbusScale = 0.0012202562538133;
-  		const double _sbusBias = -1.20988407565589;
+  		const float _sbusScale = 0.00122025625f;
+  		const float _sbusBias = -1.2098840f;
   		static const uint8_t _sbusHeader = 0x0F;
   		static const uint8_t _sbusFooter = 0x00;
   		static const uint8_t _sbusLostFrame = 0x20;

diff --git a/examples/SBUS_example/SBUS_example.ino b/examples/SBUS_example/SBUS_example.ino
@@ -2,7 +2,7 @@
 SBUS_example.ino
 Brian R Taylor
 [email protected]
-2016-07-12
+2016-09-21
 
 Copyright (c) 2016 Bolder Flight Systems
 
@@ -40,9 +40,9 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SO
 SBUS x8r(1);
 
 // channel, fail safe, and lost frames data
-int16_t channels[16];
+uint16_t channels[16];
 uint8_t failSafe;
-int lostFrames = 0;
+uint16_t lostFrames = 0;
 
 void setup() {
   // begin the SBUS communication