B4R Question INPUT_PULLDOWN - impossible ?

The INPUT_PULLDOWN mode was introduced in Arduino IDE 1.0.1 (released in 2012), but it was not supported on all microcontrollers initially.

Details:​

• Arduino AVR (ATmega-based boards like Uno, Nano) does not support INPUT_PULLDOWN in hardware, as these chips only have built-in pull-up resistors (INPUT_PULLUP).
• ARM-based Arduinos (e.g., Due, Zero) and ESP8266/ESP32 support INPUT_PULLDOWN from their initial integration into Arduino IDE.
• In Arduino SAMD Core (for boards like MKR, Nano 33 IoT) and ESP8266/ESP32 Core, this mode has been available since their first supported versions in the IDE.

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hatzisn said:

Maybe when B4R was created there were not internal pull down resistor boards.

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Since the **ESP32** family was officially supported in Arduino IDE (around **2018**), several new **MCU-specific functions and features** have been added to the IDE to support modern microcontrollers. Here are some notable additions:

---

### **1. ESP32-Specific Features (espressif/arduino-esp32)**
- **Dual-Core Support**
- `xTaskCreatePinnedToCore()` – Run FreeRTOS tasks on a specific core.
- `ARDUINO_RUNNING_CORE` – Macro to detect the current core.
- **WiFi & Bluetooth**
- `WiFi.mode(WIFI_MODE_APSTA)` – Simultaneous AP + Station mode.
- `BT.begin()` – Bluetooth Classic & BLE support.
- **Deep Sleep & Low Power**
- `esp_sleep_enable_timer_wakeup()` – Wake up after a delay.
- `esp_deep_sleep_start()` – Ultra-low-power sleep modes.
- **Peripheral Enhancements**
- **DAC (Digital-to-Analog)** – `dacWrite()` for analog output.
- **Touch Pins** – `touchRead(pin)` for capacitive sensing.
- **Hall Effect Sensor** – `hallRead()` for built-in magnetic sensing.
- **File System & NVS (Non-Volatile Storage)**
- `SPIFFS` & `LittleFS` – File system support.
- `Preferences` – Key-value storage (replaces EEPROM).

---

### **2. RP2040 (Raspberry Pi Pico) Support**
- **Dual-Core Processing**
- `setup1()` & `loop1()` – Second core execution.
- **PIO (Programmable I/O) Support**
- Allows custom state machines for bit-banging protocols.
- **Improved ADC & PWM**
- Higher resolution (12-bit ADC, 16-bit PWM).

---

### **3. STM32 (STM32duino) Enhancements**
- **Hardware-Specific Timers**
- `HardwareTimer` – Advanced PWM & interrupt control.
- **True Analog Output**
- `analogWrite()` with real DAC on supported pins.
- **Low-Power Modes**
- `LowPower.sleep()` – Multiple sleep modes.

---

### **4. ESP8266 Updates (earlier but still evolving)**
- **WiFi Improvements**
- `WiFi.softAP()` – Better access point control.
- **Over-the-Air (OTA) Updates**
- `ArduinoOTA` – Wireless firmware flashing.

---

### **5. General Arduino IDE Improvements**
- **Better Multi-Board Support**
- **Arduino CLI** – Command-line tool for managing cores.
- **New Library Manager**
- Easier installation of MCU-specific libraries.
- **Debugging Support**
- **Arduino IDE 2.0+** – Basic debugging for some ARM & ESP32 boards.

---

### **Conclusion**
Since ESP32 support was added, Arduino IDE has expanded to include **multi-core processing, advanced wireless features (WiFi/BLE), low-power modes, and better peripheral control** for modern MCUs like ESP32, RP2040, and STM32.

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hatzisn said:

implementable with pin number and InLine C.

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void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  delay(1000);
  Serial.println("Hello, ESP32!");
  Serial.print("INPUT_PULLUP = ");
  Serial.println(INPUT_PULLUP);
  Serial.print("INPUT_PULLDOWN = ");
  Serial.println(INPUT_PULLDOWN);
  Serial.print("INPUT = ");
  Serial.println(INPUT);
  Serial.print("OUTPUT = ");
  Serial.println(OUTPUT);
}

void loop() {

}

INPUT_PULLUP = 5
INPUT_PULLDOWN = 9
INPUT = 1
OUTPUT = 3

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Dim p As Pin
p.Initialize(gpio_num, 9)  'PULLDOWN

peacemaker said:

View attachment 165587

https://wokwi.com:

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  delay(1000);
  Serial.println("Hello, ESP32!");
  Serial.print("INPUT_PULLUP = ");
  Serial.println(INPUT_PULLUP);
  Serial.print("INPUT_PULLDOWN = ");
  Serial.println(INPUT_PULLDOWN);
  Serial.print("INPUT = ");
  Serial.println(INPUT);
  Serial.print("OUTPUT = ");
  Serial.println(OUTPUT);
}

void loop() {

}

So,

B4X:

Dim p As Pin
p.Initialize(gpio_num, 9)  'PULLDOWN

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(p=Pin)
p.MODE_INPUT = 0
p.MODE_OUTPUT=1
p.MODE_INPUT_PULLUP=2

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INPUT_PULLUP = 5
INPUT_PULLDOWN = 9
INPUT = 1
OUTPUT = 3

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sketch.ino:9:18: error: 'INPUT_PULLDOWN' was not declared in this scope
Serial.println(INPUT_PULLDOWN);

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Hello, STM32!
INPUT_PULLUP = 2
INPUT_PULLDOWN = 3
INPUT = 0
OUTPUT = 1

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peacemaker said:

ESP32 classic. So, it seems, each MCU has different constants in the SDK !
Google told that esp8266 does not have INPUT_PULLDOWN.

esp32-c3 also returns:



Arduino Nano board returns:



STM32:

Click to expand...

    Log(p.MODE_INPUT)
    Log(p.MODE_OUTPUT)
    Log(p.MODE_INPUT_PULLUP)

1
3
5

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