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--- arduino:arduino_crash_course:misc [2015/02/16 03:44] – mithat
+++ arduino:arduino_crash_course:misc [2015/02/16 04:22] (current) – [Serial communication] mithat
@@ Line 29: / Line 29: @@
 This leaves:
-  * **Binary out/in:** 4, 7, 8
+  * **Digital out/in:** 4, 7, 8
   * **PWM out:** 9, 10, and 11; pins 5 and 6 have higher-than-expected duty cycles.
-  * **Analog or binary out/in:** A0, A1, A2, A3
+  * **Analog or digital out/in:** A0, A1, A2, A3
+Note that pin 13 also has a pullup resistor on it for the internal LED, meaning it's a poor choice for use as an input even if you're not using SPI.
 ----
@@ Line 40: / Line 42: @@
 ==== Output ====
-=== Binary output ===
+=== Digital output ===
   * Output is limited to 40mA. More current draw can destroy the chip.
   * There are no output resistors.
@@ Line 81: / Line 83: @@
 ==== Input ====
-=== Binary input ===
+=== Digital input ===
   * "Arduino (Atmega) pins default to inputs. Approx load is 100M ohm." ((http://arduino.cc/en/Tutorial/DigitalPins))
   * Internal pullup resistors are disabled by default.
@@ Line 125: / Line 127: @@
 int ANALOG_PIN = 3;  // Maps to A3 we think.
 int val = 0;
-...
 void loop() {
@@ Line 134: / Line 134: @@
+----
+===== Serial communication =====
+  * Serial I/O consumes pins 0 (for RX) and 1 (for TX) if used.
+  * [[http://arduino.cc/en/Reference/Serial|Serial reference]]
+==== Serial output ====
+Simple reporting:
+<code c>
+void setup() {
+  Serial.begin(9600);  // init serial communication at 9600 bps
+}
+void loop() {
+  Serial.write(65);           // write a byte (interpreted as ASCII)
+  Serial.print(42);           // print a number
+  Serial.println("Yo.");      // print a string as a line
+  Serial.print(78, HEX);      // print "4E"
+  Serial.println(1.23456, 4); // print "1.2346"
+  Serial.end();               // release pins 0 and 1 for general use
+}
+</code>
+==== Serial output ====
+Later.
+----