Nucleo-F103RB - USART2 printf not working on Tera Term (No Output Displayed)

[김형건]

Hello,

I am working with a Nucleo-F103RB board and trying to send printf output over UART using USART2. I have configured UART2 with the following parameters:

Baud rate: 9600

Word length: 8 bits

Stop bits: 1

Parity: None

Mode: TX/RX

I also redirected printf to HAL_UART_Transmit() via __io_putchar() as shown below:

PUTCHAR_PROTOTYPE
{
  HAL_UART_Transmit(&huart2, (uint8_t *)&ch, 1, 0xFFFF);
  return ch;
}

In my main() loop, I am calling printf() every second like this:

uint8_t count = 0;
float f = 1.234;

while (1)
{
  printf("hello : %d, %f\r\n", count++, f++);
  HAL_Delay(1000);
}

However, nothing is being printed in Tera Term (v5.0).
I selected the correct COM port and set it to 9600 baud rate. Other serial settings are default and matched.

I have verified that:

MX_USART2_UART_Init() is called in main.c

GPIOs are configured by CubeMX for USART2 (PA2: TX, PA3: RX)

No errors are reported during initialization.

But still, I see no output on Tera Term.

How can I troubleshoot or resolve this issue?
Is there anything wrong in the way printf is being redirected or in UART2 configuration?

Any help or suggestions would be greatly appreciated!

Thanks.

---

Edited to apple source code formatting - see How to insert source code for future reference

[Andrew Neil]

Before worrying about the printf redirection, does HAL_UART_Transmit()  work alone?

If that doesn't work, then you need to find & fix that before you have any chance of printf working!

EDIT: Also try just plain text - special support may be required for floats

---

@김형건 wrote:

I am working with a Nucleo-F103RB board and trying to send printf output over UART using USART2.

---

So how is that connected through to your TeraTerm?

If you're using the ST-Link's VCP (Virtual COM Port), make sure that you're using the correct UART, and the correct pins, and the correct configuration of the board - see the board's User Manual and Schematics for details.

[raptorhal2]

Perhaps you are missing this:

/* Enable USART2 clock */
USART2_CLK_ENABLE();