Micro-RLE ≤264-byte compression for UART/MCU logs, zero RAM growth
I needed to stuff twice the telemetry through the same 115 kbaud line on a Cortex-M0+ that only had 8 kB flash left. Micro-RLE is the smallest drop-in I could come up with: 264 B of Thumb code, 36 B of state, no malloc, worst-case 14 cycles/byte and still lossless for every 8-bit pattern. On the usual sensor streams (ADC, IMU, GPS) it’s 33-70 % smaller than raw output and boots in < 600 µs, so you can fire-and-forget from main() before the PLL even locks. Repo is a single .c file and a 3-function API—replace the weak emit() hook with your UART / DMA / ring-buffer and you’re…
What it does
In the maker’s words, at launch
I needed to stuff twice the telemetry through the same 115 kbaud line on a Cortex-M0+ that only had 8 kB flash left. Micro-RLE is the smallest drop-in I could come up with: 264 B of Thumb code, 36 B of state, no malloc, worst-case 14 cycles/byte and still lossless for every 8-bit pattern. On the usual sensor streams (ADC, IMU, GPS) it’s 33-70 % smaller than raw output and boots in < 600 µs, so you can fire-and-forget from main() before the PLL even locks. Repo is a single .c file and a 3-function API—replace the weak emit() hook with your UART / DMA / ring-buffer and you’re done. Size proof: arm-none-eabi-size micro_rle.o text data bss 264 0 36 MIT licensed, link in the repo. Happy to hear where else this fits!
Does the same job
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