Fixes RMT filter & idle timing and setup (#8359)

* Fixes Filter and Idle parameter to uint32

* Fixes Filter and Idle setup

* Fixes it to 5.1Libs branch

* fix RMT CLK source and Filter API

* fixes missing ;

* fixes missing ;

* fixes RMT example

Author: SuGlider

cores/esp32/esp32-hal-rmt.c

@@ -19,6 +19,7 @@
 #include "driver/gpio.h"
 #include "driver/rmt_tx.h"
 #include "driver/rmt_rx.h"
+#include "hal/rmt_ll.h"
 
 #include "esp32-hal-rmt.h"
 #include "esp32-hal-periman.h"
@@ -58,6 +59,7 @@ struct rmt_obj_s {
   EventGroupHandle_t rmt_events;             // read/write done event RMT callback handle
   bool rmt_ch_is_looping;                    // Is this RMT TX Channel in LOOPING MODE?
   size_t *num_symbols_read;                  // Pointer to the number of RMT symbol read by IDF RMT RX Done
+  uint32_t frequency_Hz;                     // RMT Frequency
 
 #if !CONFIG_DISABLE_HAL_LOCKS
   SemaphoreHandle_t g_rmt_objlocks;           // Channel Semaphore Lock
@@ -210,7 +212,7 @@ bool rmtSetCarrier(int pin, bool carrier_en, bool carrier_level, uint32_t freque
   return retCode;
 }
 
-bool rmtSetFilter(int pin, uint8_t filter_pulse_ns)
+bool rmtSetRxMinThreshold(int pin, uint8_t filter_pulse_ticks)
 {
   rmt_bus_handle_t bus = _rmtGetBus(pin, __FUNCTION__);
   if (bus == NULL) {
@@ -221,13 +223,23 @@ bool rmtSetFilter(int pin, uint8_t filter_pulse_ns)
     return false;
   }
 
+  uint32_t filter_pulse_ns = (1000000000 / bus->frequency_Hz) * filter_pulse_ticks;
+  // RMT_LL_MAX_FILTER_VALUE is 255 for ESP32, S2, S3, C3, C6 and H2;
+  // filter_pulse_ticks is 8 bits, thus it will not exceed 255
+#if 0 // for the future, in case some other SoC has different limit
+  if (filter_pulse_ticks > RMT_LL_MAX_FILTER_VALUE) {
+    log_e("filter_pulse_ticks is too big. Max = %d", RMT_LL_MAX_FILTER_VALUE);
+    return false;
+  }
+#endif
+
   RMT_MUTEX_LOCK(bus);
   bus->signal_range_min_ns = filter_pulse_ns; // set zero to disable it
   RMT_MUTEX_UNLOCK(bus);
   return true;
 }
 
-bool rmtSetRxThreshold(int pin, uint16_t value)
+bool rmtSetRxMaxThreshold(int pin, uint16_t idle_thres_ticks)
 {
   rmt_bus_handle_t bus = _rmtGetBus(pin, __FUNCTION__);
   if (bus == NULL) {
@@ -238,8 +250,17 @@ bool rmtSetRxThreshold(int pin, uint16_t value)
     return false;
   }
 
+  uint32_t idle_thres_ns = (1000000000 / bus->frequency_Hz) * idle_thres_ticks;
+  // RMT_LL_MAX_IDLE_VALUE is 65535 for ESP32,S2 and 32767 for S3, C3, C6 and H2
+#if RMT_LL_MAX_IDLE_VALUE < 65535 // idle_thres_ticks is 16 bits anyway - save some bytes
+  if (idle_thres_ticks > RMT_LL_MAX_IDLE_VALUE) {
+    log_e("idle_thres_ticks is too big. Max = %ld", RMT_LL_MAX_IDLE_VALUE);
+    return false;
+  }
+#endif
+
   RMT_MUTEX_LOCK(bus);
-  bus->signal_range_max_ns = value; // set as zero to disable it
+  bus->signal_range_max_ns = idle_thres_ns;
   RMT_MUTEX_UNLOCK(bus);
   return true;
 }
@@ -462,10 +483,12 @@ bool rmtInit(int pin, rmt_ch_dir_t channel_direction, rmt_reserve_memsize_t mem_
     goto Err;
   }
 
+  // store the RMT Freq to check Filter and Idle valid values in the RMT API
+  bus->frequency_Hz = frequency_Hz;
   // pulses with width smaller than min_ns will be ignored (as a glitch)
-  bus->signal_range_min_ns = 1000000000 / (frequency_Hz * 2); // 1/2 pulse width
+  bus->signal_range_min_ns = 0; // disabled
   // RMT stops reading if the input stays idle for longer than max_ns
-  bus->signal_range_max_ns = (1000000000 / frequency_Hz) * 10; // 10 pulses width
+  bus->signal_range_max_ns = (1000000000 / frequency_Hz) * RMT_LL_MAX_IDLE_VALUE; // maximum possible
   // creates the event group to control read_done and write_done
   bus->rmt_events = xEventGroupCreate();
   if (bus->rmt_events == NULL) {

cores/esp32/esp32-hal-rmt.h

@@ -177,14 +177,14 @@ bool rmtReadAsync(int pin, rmt_data_t* data, size_t *num_rmt_symbols);
 bool rmtReceiveCompleted(int pin);
 
 /**
-   Function used to set a threshold for the time used to consider that a data reception has ended.
-   In receive mode, when no edge is detected on the input signal for longer than idle_thres 
-   channel clock cycles, the receiving process is finished and the Data is made available by 
+   Function used to set a threshold (in ticks) used to consider that a data reception has ended.
+   In receive mode, when no edge is detected on the input signal for longer than idle_thres_ticks 
+   time, the receiving process is finished and the Data is made available by 
    the rmtRead/Async functions. Note that this time (in RMT channel frequency cycles) will also
-   define how many low bits are read at the end of the received data.
+   define how many low/high bits are read at the end of the received data.
    The function returns <true> if it is correctly executed, <false> otherwise.
 */
-bool rmtSetRxThreshold(int pin, uint16_t value);
+bool rmtSetRxMaxThreshold(int pin, uint16_t idle_thres_ticks);
 
 /**
    Parameters changed in Arduino Core 3: low and high (ticks) are now expressed in Carrier Freq in Hz and
@@ -201,11 +201,12 @@ bool rmtSetCarrier(int pin, bool carrier_en, bool carrier_level, uint32_t freque
 
 /**
    Function used to filter input noise in the RX channel.
-   In receiving mode, channel will ignore any input pulse which width is smaller than <filter_pulse_ns>
-   If <filter_level> is Zero, it will to disable the filter.
+   In receiving mode, channel will ignore any input pulse which width (high or low) 
+   is smaller than <filter_pulse_ticks>
+   If <filter_pulse_ns> is Zero, it will to disable the filter.
    The function returns <true> if it is correctly executed, <false> otherwise.
 */
-bool rmtSetFilter(int pin, uint8_t filter_level);
+bool rmtSetRxMinThreshold(int pin, uint8_t filter_pulse_ticks);
 
 /**
    Deinitializes the driver and releases all allocated memory

libraries/ESP32/examples/RMT/RMTLoopback/RMTLoopback.ino

@@ -37,7 +37,7 @@ rmt_data_t data[256];
 
 static EventGroupHandle_t events;
 
-#define RMT_FREQ 10000000
+#define RMT_FREQ 10000000          // tick time is 100ns
 #define RMT_NUM_EXCHANGED_DATA 30
 
 void setup() {
@@ -51,10 +51,10 @@ void setup() {
         Serial.println("init receiver failed\n");
     }
 
-    // End of transmission shall be detected when line is idle for 2us
-    rmtSetRxThreshold(RMT_RX_PIN, 2000);
+    // End of transmission shall be detected when line is idle for 2us = 20*100ns
+    rmtSetRxMaxThreshold(RMT_RX_PIN, 20);
     // Disable Glitch  filter
-    rmtSetFilter(RMT_RX_PIN, 0);  
+    rmtSetRxMinThreshold(RMT_RX_PIN, 0);  
 
     Serial.println("real tick set to: 100ns");
     Serial.printf("\nPlease connect GPIO %d to GPIO %d, now.\n", RMT_TX_PIN, RMT_RX_PIN);