When Curious Scientist launched their CH32V003F4P6 – USART basics tutorial, it felt like uncovering a secret superpower. It takes things further than GPIO: you learn how to receive characters from your PC, echo them back, and even toggle LEDs based on serial commands—all using that humble serial link between your chip and terminal.
Their guided example:
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Sets up a non-blocking
echoCharacterUSART()routine: reads theRXNEflag, grabs the data, and immediately sends it back. -
Lets you issue simple commands from your PC to toggle LEDs (characters ‘1’ through ‘4’).
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Demonstrates how serial input can control behavior—without messing up your main loop too badly Curious Scientist.
It’s a solid foundation, especially if you want to send a command to start ADC sampling, or control sensors, or just impress your friends by blinking lights from the terminal.
The Legendary Birth of UART: From Room-Sized Boards to Tiny Chips
Let’s take a time machine back to the 1960s. DEC engineer Gordon Bell needed a reliable way to connect Teletype machines to a PDP‑1 computer. The solution? A sampling-based all-digital interface—the first UART, built on a circuit-board-sized module that could overload your desk.
By 1971, Western Digital bottled that magic in a single chip—the WD1402A UART, freeing devices from the tedium of hand‑tuned analog circuits. From there, chips like the National 8250, and later the 16550 with its FIFO buffer, became serialized standards in the IBM PCs and modems of the '80s and '90s.
Today, UART isn't flashy, but it survives in every MCU, router console, and embedded debug port—even though we've got USB and Ethernet that are way faster and cooler.
How UART Actually Works (Without Falling Asleep)
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Asynchronous transmission: No shared clock. Instead each byte is wrapped in start-bit and stop-bit gates.
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Data framing: Usually 5–8 data bits, optional parity, and stop bits (1–2) to mark byte boundaries.
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Baud rate synchronization: Both sides must agree on bit timing—typically within 90% accuracy or things go weird. Line signaling: Idle lines sit “high” (thanks Morse‑code heritage), and transitions represent data.
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Flow control & buffering: Early UARTs offered simple serial handshake; later the 16550 introduced a 16‑byte FIFO to buffer incoming data—no more dropped characters if the CPU gets sluggish.
UART chips either stand alone or come built into microcontrollers—such as the USART peripheral in the CH32V003F4P6 (which can also do synchronous mode if you’re into that).
Why It Still Matters—with a CH32V003F4P6 Twist
The Curious Scientist tutorial gives you a hands‑on start. But understanding the tech legacy and UART mechanics turns you from a copy‑paster into a serial-savvy hacker.
With the CH32V003F4P6, you’re dealing with:
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Full-duplex USART1 with RXNE and TXE flags
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Interrupt-capable routines like
echoCharacterUSART() -
Command-based LED toggling (like
'1','2', etc.) -
Future-proof ability to trigger ADC reads via serial commands, or send sensor data back to the PC—all at your whim
Want the full tutorial? Check it here and say "hi" to the Curious Scientist from out part:
