Reliable delivery
Strict stop-and-wait ARQ waits for ACK and retries when a frame is lost or rejected.
Universal Reliable Serial Transport
Reliable serial messages for MicroPython boards.
URST-mpy turns a plain UART link into a dependable message channel. It handles framing, CRC checks, acknowledgements, retries, and message fragmentation for boards such as the Raspberry Pi Pico and ESP32.
- Handlersend() and read()
- ProtocolCONNECT, ACK, NAK, retry
- Transportframe type, sequence, fragments
- CodecCOBS, CRC-16, UART I/O
Why use it
Built for links that are useful but not perfect
Error checked frames
Every frame carries CRC-16/CCITT-FALSE validation, with COBS encoding for unambiguous zero-delimited framing.
Large message support
Messages larger than the physical MTU are fragmented and reassembled automatically by the transport.
Hardware agnostic
Use the same transport with MicroPython UART objects or desktop Python serial ports for gateways and tests.
Quick start
Install it on a board
Install directly with mpremote mip, or copy theurst/ package onto your MicroPython filesystem. Then pass URST a UART object and work with complete byte messages instead of raw serial chunks.
mpremote mip install github:simonl65/URST-mpyExample
A small API over a noisy link
URST-mpy keeps application code direct: initialize the transport, send bytes, and poll for complete reassembled messages.
import machine
import time
import urst
uart = machine.UART(
0,
baudrate=57600,
tx=machine.Pin(0),
rx=machine.Pin(1),
)
transport = urst.Urst(uart)
transport.send(b"Hello from Pico!")
while True:
message = transport.read()
if message:
print("Received:", message.decode())
time.sleep(0.1)