Add clock selection to RFControl (80 MHz or 1 MHz)

Added second argument to RFControl(uint8_t pin, boolean refClock=true) to allow choice of Ref Tick (1 MHz) clock or APB (80 MHz) clock.  Default is to use 1 MHz Ref Tick.

Also fixed bug in logic that divides clock for ESP32-C3.  Factor should be 79, not 80, since divider is apparently configured to divide by factor+1.

src/extras/RFControl.cpp

@@ -6,7 +6,7 @@
 
 ///////////////////
 
-RFControl::RFControl(uint8_t pin){
+RFControl::RFControl(uint8_t pin, boolean refClock){
 
 #ifdef CONFIG_IDF_TARGET_ESP32C3
   if(nChannels==RMT_CHANNEL_MAX/2){
@@ -34,10 +34,11 @@ RFControl::RFControl(uint8_t pin){
   rmt_config(config);
   rmt_driver_install(config->channel,0,0);
 
-  // Below we set the base clock to 1 MHz so tick-units are in microseconds (before CLK_DIV)
+  // If specified, set the base clock to 1 MHz so tick-units are in microseconds (before any CLK_DIV is applied), otherwise default will be 80 MHz APB clock
 
+  if(refClock)
 #ifdef CONFIG_IDF_TARGET_ESP32C3
-  REG_SET_FIELD(RMT_SYS_CONF_REG,RMT_SCLK_DIV_NUM,80);        // ESP32-C3 does not have a 1 MHz REF Tick Clock, but allows the 80 MHz APB clock to be scaled by an additional RMT-specific divider
+  REG_SET_FIELD(RMT_SYS_CONF_REG,RMT_SCLK_DIV_NUM,79);        // ESP32-C3 does not have a 1 MHz REF Tick Clock, but allows the 80 MHz APB clock to be scaled by an additional RMT-specific divider
 #else  
   rmt_set_source_clk(config->channel,RMT_BASECLK_REF);        // use 1 MHz REF Tick Clock for ESP32 and ESP32-S2
 #endif

src/extras/RFControl.h

@@ -16,7 +16,7 @@ class RFControl {
     static uint8_t nChannels;
                                
   public:    
-    RFControl(uint8_t pin);                                                           // creates transmitter on pin   
+    RFControl(uint8_t pin, boolean refClock=true);                                    // creates transmitter on pin, using 1-MHz Ref Tick clock
     
     void start(uint32_t *data, int nData, uint8_t nCycles=1, uint8_t tickTime=1);     // starts transmission of pulses from specified data pointer, repeated for numCycles, where each tick in pulse is tickTime microseconds long
     void start(uint8_t nCycles=1, uint8_t tickTime=1);                                // starts transmission of pulses from internal data structure, repeated for numCycles, where each tick in pulse is tickTime microseconds long    

src/extras/extras.ino

@@ -10,32 +10,20 @@ void setup() {
 
   Serial.println("\n\nHomeSpan RF Transmitter Example");
 
-  RFControl rf(17);               // create an instance of RFControl with signal output to pin 17
+  RFControl rf(10);               // create an instance of RFControl with signal output to pin 17
 
   rf.clear();
 
   rf.add(10000,10000);
   rf.add(10000,10000);
-  rf.add(10000,40000);
+  rf.add(10000,30000);
 
   uint32_t t0=micros();
-  rf.start(4,100);
+  rf.start(4,1);
   uint32_t t1=micros();
    
   Serial.println("End Example");
   Serial.println((t1-t0)/1000);
-  
-  rf.clear();
-
-  rf.add(10000,10000);
-  rf.add(10000,10000);
-
-  t0=micros();
-  rf.start(4,100);
-  t1=micros();
-   
-  Serial.println("End Example");
-  Serial.println((t1-t0)/1000);
 
 } // end of setup()