Added RMT Step Generation as an option

- Uncomment #define USE_RMT_STEPS in config.h to use RMT based steps
- You can also use #define STEP_PULSE_DELAY 10 in config.h now

Grbl_Esp32/config.h

@@ -49,6 +49,7 @@ Some features should not be changed. See notes below.
 #define CPU_MAP_ESP32 // these are defined in cpu_map.h
 #define VERBOSE_HELP // adds addition help info, but could confuse some senders
 
+
 // Serial baud rate
 #define BAUD_RATE 115200
 
@@ -501,6 +502,15 @@ Some features should not be changed. See notes below.
 // time step. Also, keep in mind that the Arduino delay timer is not very accurate for long delays.
 #define DWELL_TIME_STEP 50 // Integer (1-255) (milliseconds)
 
+
+// For test use only. This uses the ESP32's RMT perifieral to generate step pulses
+// It allows the use of the STEP_PULSE_DELAY (see below) and it automatically ends the
+// pulse in one operation.
+// Dir Pin  ____|--------------------
+// Step Pin _______|--|____________
+// While this is experimental, it is intended to be the future default method after testing
+//#define USE_RMT_STEPS
+
 // Creates a delay between the direction pin setting and corresponding step pulse by creating
 // another interrupt (Timer2 compare) to manage it. The main Grbl interrupt (Timer1 compare)
 // sets the direction pins, and does not immediately set the stepper pins, as it would in
@@ -510,8 +520,8 @@ Some features should not be changed. See notes below.
 // NOTE: Uncomment to enable. The recommended delay must be > 3us, and, when added with the
 // user-supplied step pulse time, the total time must not exceed 127us. Reported successful
 // values for certain setups have ranged from 5 to 20us.
-// !!!!! ESP32 Not currently implemented
-// #define STEP_PULSE_DELAY 10 // Step pulse delay in microseconds. Default disabled.
+// must use #define USE_RMT_STEPS for this to work
+//#define STEP_PULSE_DELAY 10 // Step pulse delay in microseconds. Default disabled.
 
 // The number of linear motions in the planner buffer to be planned at any give time. The vast
 // majority of RAM that Grbl uses is based on this buffer size. Only increase if there is extra

Grbl_Esp32/cpu_map.h

@@ -35,7 +35,9 @@
 	with AVR grbl
 	
 	*/
-	
+		
+
+
 #ifdef CPU_MAP_ESP32
 	// This is the CPU Map for the ESP32 CNC Controller R2	
 	
@@ -43,13 +45,17 @@
     // won't affect operation except that there will be no output
 		// form the pins. Grbl will virtually move the axis. This could 
 		// be handy if you are using a servo, etc. for another axis.
-		#define X_STEP_PIN      GPIO_NUM_12
-		#define Y_STEP_PIN      GPIO_NUM_14
-    #define Z_STEP_PIN      GPIO_NUM_27		
+		#define X_STEP_PIN      	GPIO_NUM_12
+		#define X_DIRECTION_PIN  	GPIO_NUM_26
+		#define X_RMT_CHANNEL		0
 		
-		#define X_DIRECTION_PIN   GPIO_NUM_26
-		#define Y_DIRECTION_PIN   GPIO_NUM_25  
-		#define Z_DIRECTION_PIN   GPIO_NUM_33 
+		#define Y_STEP_PIN      	GPIO_NUM_14
+		#define Y_DIRECTION_PIN   	GPIO_NUM_25
+		#define Y_RMT_CHANNEL		1
+		
+		#define Z_STEP_PIN      	GPIO_NUM_27		
+		#define Z_DIRECTION_PIN   	GPIO_NUM_33 		 
+		#define Z_RMT_CHANNEL		2		
 		
 		// OK to comment out to use pin for other features
 		#define STEPPERS_DISABLE_PIN GPIO_NUM_13		
@@ -851,4 +857,3 @@
 		
 		
 #endif
-

Grbl_Esp32/stepper.h

@@ -82,6 +82,8 @@ extern uint8_t ganged_mode;
 void IRAM_ATTR onSteppertimer();
 void IRAM_ATTR onStepperOffTimer();
 void stepper_init();
+void initRMT(); 
+inline IRAM_ATTR static void stepperRMT_Outputs();
 
 // Enable steppers, but cycle does not start unless called by motion control or realtime command.
 void st_wake_up();