ESP8266 Developer Zone

system_adc_read_fast acquires only 255 samples

With a bigger number of samples the function freezes and the watchdog resets the chip. NONOS 2.0

Please use consecutive calls to the fast read API to get ADC samples. The buffer for the API is probably internally limited (I am not very familiar with exact internal implementation of the API). Call system_soft_wdt_reset() as well before initiating fast_read API.