Differences

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--- esp32:direct_pin_data_copy [2019/09/26 20:47] – aistis
+++ esp32:direct_pin_data_copy [2019/09/27 07:34] (current) – aistis
@@ Line 1: / Line 1: @@
 copy data from input pin to output pin - example ws8212 data stream
+fast way to copy read/write register values
 <code cpp>
 void loop() {
+  int v1 = 0;
-  uint64_t cnt = 0;
-  register uint32_t cnt2 = 0;
-  //disableCore0WDT();
-  //disableCore1WDT();
   portDISABLE_INTERRUPTS();
-  //disableCore0WDT();
+  for(;;) {
-  //disableCore1WDT();
+    auto v1 = (GPIO_REG_READ(GPIO_IN_REG) & BIT(25));
-  gpio_num_t pin = (gpio_num_t)(25 & 0x1F);
+    if (v1) {
-  int state=0;
+       GPIO_REG_WRITE(GPIO_OUT_W1TS_REG, BIT(27));
-  register int v1 = digitalRead(25);
+       //cnt3 = 0;
-  register int p1 = digitalRead(25);
-  for (;;) {
-    v1 = (GPIO_REG_READ(GPIO_IN_REG)  >> pin) & 1U;
-    if (v1 != p1)
-    {
-      digitalWrite(27, v1);
-      p1 = v1;
     }
-    cnt2 ++;
+    else {
-    if (cnt2 % 1000000 == 0) {
+      GPIO_REG_WRITE(GPIO_OUT_W1TC_REG, BIT(27));
+      //cnt3 ++;
+    }
+    cnt3 ++;
+    if (cnt3 % 1000000 == 0) {
       //Serial.println("loop");
       portENABLE_INTERRUPTS();
+      vTaskDelay(10);
       portDISABLE_INTERRUPTS();
     }
   }
 }
+</code>
+speed is like 3.5 times faster
+  * 07:31:40.620 -> register based read : 53
+  * 07:31:40.620 -> digitalRead based read : 172
+<code>
+  auto t1 = micros();
+  int v1;
+  for (int i=0;i<1000;i++)
+    v1 = (GPIO_REG_READ(GPIO_IN_REG) & BIT(25));
+  auto t2 = micros();
+  auto t3 = micros();
+  for (int i=0;i<1000;i++)
+    v1 = digitalRead(25);
+  auto t4 = micros();
+  Serial.printf("register based read : %d\n",t2-t1);
+  Serial.printf("digitalRead based read : %d\n",t4-t3);
 </code>