esp8266:how-to-use-all-esp01-gpio-pins
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esp8266:how-to-use-all-esp01-gpio-pins [2019/10/23 15:24] Ilias Iliopoulos [Introduction] WeeMos D1 to WeMos D1 |
esp8266:how-to-use-all-esp01-gpio-pins [2019/10/31 20:38] Ilias Iliopoulos Modified code blocks to <code c++> |
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| - | ====== How to use all ESP-01 GPIO pins ====== | + | ====== How to use "all" ESP-01 GPIO pins ====== |
| ===== Introduction ===== | ===== Introduction ===== | ||
| Line 54: | Line 54: | ||
| The solution is to implement a **negative logic** in our code. This means that HIGH voltage on the pin will signify an **"Off"** state, whereas a LOW voltage will be the **"On"** state. The circuit to implement this method employs a PNP transistor, followed by an NPN transistor. In this example circuit, a relay is driven by GPIO0. When we want to activate the relay, we write LOW to pin 0: | The solution is to implement a **negative logic** in our code. This means that HIGH voltage on the pin will signify an **"Off"** state, whereas a LOW voltage will be the **"On"** state. The circuit to implement this method employs a PNP transistor, followed by an NPN transistor. In this example circuit, a relay is driven by GPIO0. When we want to activate the relay, we write LOW to pin 0: | ||
| - | <code> | + | <code c++> |
| digitalWrite(0, LOW); | digitalWrite(0, LOW); | ||
| </code> | </code> | ||
| Line 60: | Line 60: | ||
| And when we want to de-activate the relay, we write HIGH. | And when we want to de-activate the relay, we write HIGH. | ||
| - | <code> | + | <code c++> |
| digitalWrite(0, HIGH); | digitalWrite(0, HIGH); | ||
| </code> | </code> | ||
| Line 66: | Line 66: | ||
| Because I try to write code that can be re-used in several projects, I introduce a constant such as **gpioLogic** and the code goes like: | Because I try to write code that can be re-used in several projects, I introduce a constant such as **gpioLogic** and the code goes like: | ||
| - | <code> | + | <code c++> |
| /* | /* | ||
| Set true for a positive logic or false for a negative logic | Set true for a positive logic or false for a negative logic | ||
| Line 118: | Line 118: | ||
| In terms of software, in order to force pins TXD/GPIO1 and RXD/GPIO3 to operate as I2C pins functioning as SDA and SCL respectively, we must set in our code: | In terms of software, in order to force pins TXD/GPIO1 and RXD/GPIO3 to operate as I2C pins functioning as SDA and SCL respectively, we must set in our code: | ||
| - | <code> | + | <code c++> |
| Wire.begin(1, 3) | Wire.begin(1, 3) | ||
| </code> | </code> | ||
| Line 124: | Line 124: | ||
| The syntax is: | The syntax is: | ||
| - | <code> | + | <code c++> |
| Wire.begin(sda_pin, scl_pin). | Wire.begin(sda_pin, scl_pin). | ||
| </code> | </code> | ||
esp8266/how-to-use-all-esp01-gpio-pins.txt ยท Last modified: 2024/02/02 21:49 by Ilias Iliopoulos