Arduino: Start Serial with only TX enabled

[supersjimmie]

Hardware

Hardware: NodeMCU v2
Core Version: Latest GIT

Description

Problem description

Settings in IDE

Module: NodeMCU
Upload Using: SERIAL
Reset Method: nodemcu

Sketch

#include "DHT.h"
#define DHTTYPE DHT22
#define DHTPIN D9  //  D9 is Serial RX
DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);
  dht.begin();
}

void loop() {
  Serial.println(dht.readTemperature());
}

This is a stripped version of my code, which just describes the question.
I would like to use pin D9 for DHT (input), because I only use Serial for debugging output.
Is it possible to begin Serial with some parameter so it will only use it's TX pin and leave the RX pin free/available for other usage?

I do see this in the uart.h file, but I really don't know if/how I could make use of those:

#define UART_FULL     0
#define UART_RX_ONLY  1
#define UART_TX_ONLY  2

#define UART_TX_FIFO_SIZE 0x80

struct uart_;
typedef struct uart_ uart_t;

uart_t* uart_init(int uart_nr, int baudrate, int config, int mode, int tx_pin, size_t rx_size);
void uart_uninit(uart_t* uart);

void uart_swap(uart_t* uart, int tx_pin);
void uart_set_tx(uart_t* uart, int tx_pin);
void uart_set_pins(uart_t* uart, int tx, int rx);
bool uart_tx_enabled(uart_t* uart);
bool uart_rx_enabled(uart_t* uart);

[WereCatf]

Looking at the HardwareSerial.h it looks like Serial.begin(115200, SERIAL_8N1, SERIAL_TX_ONLY); would do the trick.

[supersjimmie]

I tried this and it compiles and outputs my debugging:

  Serial.begin(115200, SERIAL_8N1, SERIAL_TX_ONLY, 1);   //     void begin(unsigned long baud, SerialConfig config, SerialMode mode, uint8_t tx_pin);

But it seems that the D9 is still not usable, because the DHT still does not communicate.

[WereCatf]

Does it work if you try it on some other pin?

[supersjimmie]

You're just a second faster than me.
Reverted back to D4 where it worked and that stopped working, so I guess I have another hardware issue now. Will come back later...

[supersjimmie]

Thanks @WereCatf
Yep, works now.
I can upload a new sketch with the DHT connected to D9 (RX) and use the DHT when running.
(only my DHT22 modules are getting crappy, sometimes they don't work at any pin anymore)

[WereCatf]

Good to hear :)