https://github.com/eriksl/esp8266-unive ... ses/tag/19
This release adds
- compiler upgraded from gcc 4.8.5 to gcc 7.4.0 (experimental!)
- various options to reduce code size (IRAM) (experimental!)
- toolchain now included in the project, so if you want to build yourself, you only need: gcc, make, git and esptool.py; all the rest will be built from the project if you run "make"; no need for any SDKs or toolchains.
- flags to select polarity of the TX/RX pins of both uarts:
* uart0-tx-inv
* uart0-rx-inv
* uart1-tx-inv
use flag-set to enable or flag-unset to disable inversion, then write config, then reset.