3.3.7

libraries/ESP32/examples/RMT/RMTCallback/RMTCallback.ino

@@ -0,0 +1,98 @@
+// Copyright 2023 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/**
+ * @brief This example demonstrate how to use a C++ Class to read several GPIO RMT signals
+ * calling a data processor when data is available in background, using tasks.
+ *
+ * The output is the last RMT data read in the GPIO, just to illustrate how it works.
+ *
+ */
+
+class MyProcessor {
+private:
+  uint32_t buff;  // rolling buffer of most recent 32 bits.
+  int at = 0;
+  size_t rx_num_symbols = RMT_MEM_NUM_BLOCKS_1 * RMT_SYMBOLS_PER_CHANNEL_BLOCK;
+  rmt_data_t rx_symbols[RMT_MEM_NUM_BLOCKS_1 * RMT_SYMBOLS_PER_CHANNEL_BLOCK];
+
+public:
+  int8_t gpio = -1;
+
+  MyProcessor(uint8_t pin, uint32_t rmtFreqHz) {
+    if (!rmtInit(pin, RMT_RX_MODE, RMT_MEM_NUM_BLOCKS_1, rmtFreqHz)) {
+      Serial.println("init receiver failed\n");
+      return;
+    }
+    gpio = pin;
+  }
+
+  void begin() {
+    // Creating RMT RX Callback Task
+    xTaskCreate(readTask, "MyProcessor", 2048, this, 4, NULL);
+  }
+
+  static void readTask(void *args) {
+    MyProcessor *me = (MyProcessor *)args;
+
+    while (1) {
+      // blocks until RMT has read data
+      rmtRead(me->gpio, me->rx_symbols, &me->rx_num_symbols, RMT_WAIT_FOR_EVER);
+      // process the data like a callback whenever there is data available
+      process(me->rx_symbols, me->rx_num_symbols, me);
+    }
+    vTaskDelete(NULL);
+  }
+
+  static void process(rmt_data_t *data, size_t len, void *args) {
+    MyProcessor *me = (MyProcessor *)args;
+    uint32_t *buff = &me->buff;
+
+    for (int i = 0; len; len--) {
+      if (data[i].duration0 == 0) {
+        break;
+      }
+      *buff = (*buff << 1) | (data[i].level0 ? 1 : 0);
+      i++;
+
+      if (data[i].duration1 == 0) {
+        break;
+      }
+      *buff = (*buff << 1) | (data[i].level1 ? 1 : 0);
+      i++;
+    };
+  }
+
+  uint32_t val() {
+    return buff;
+  }
+};
+
+// Attach 3 processors to GPIO 4, 5 and 10 with different tick/speeds.
+MyProcessor mp1 = MyProcessor(4, 1000000);
+MyProcessor mp2 = MyProcessor(5, 1000000);
+MyProcessor mp3 = MyProcessor(10, 2000000);
+
+void setup() {
+  Serial.begin(115200);
+  mp1.begin();
+  mp2.begin();
+  mp3.begin();
+}
+
+void loop() {
+  // The reading values will come from the 3 tasks started by setup()
+  Serial.printf("GPIO %d: %08lx | %d: %08lx | %d: %08lx\n", mp1.gpio, mp1.val(), mp2.gpio, mp2.val(), mp3.gpio, mp3.val());
+  delay(500);
+}