# In an ADC, Does UART baud rate affect signal transmission even if they are stored and retrieved from memory?

If I'm using a NUCLEO-F401RE with ADC throughput rate greater than 2 MSPS and storing the value in an array/memory, will the UART baud rate affect transmission of the signals from memory? How are they related?

I want a 200 kHz input signal sampled at 2 MSPS & transmitted through UART. Is it possible, if not why?

• We need to know the data rate for which we need to know how big each sample is and the data transport format: no. of data bits, no. of stop bits, yes or no parity bit. – Oldfart May 16 at 7:10
• If 2'000'000*(ADC width) is more than what your UART throughput is, then it won't work. – Humpawumpa May 16 at 7:14
• Why would you sample a 200 kHz signal at 2 MS/s? That's oversampling by a factor of 5! Unless you have a clear mathematical reason to want oversampling, I'd strongly advise you to take a step back and think about your overall system design and what rate you need where. – Marcus Müller May 16 at 7:36
• @Oldfart The ADC resolution is 12 bit. The data format is 1 startbit,8 databits &1 stopbit. – Archana Narayanan May 16 at 9:18
• Aha! So, while the data rate might be 200 kHz (capitalization matters! What you write would be pronounce "kelvinhertz"), that means it has frequency components much higher. Check whether your anti-aliasing filter is sufficient. Anyways, I don't really understand how you think you can squeeze 2 Millions of continuous samples per second, which equates to 30 Million bits per second, through an UART with a maximum bit rate of less than 10 Million bits per second. What's not to understand about the impossibility of that? – Marcus Müller May 16 at 10:43

The STM32F401RE MCU on the board has a maximum APB2 clock frequency of 84 MHz. The maximal UART bitrate is 1/8 of the clock, that's 10.5 MBits/s.