https://docs.ai-thinker.com/_media/esp8 ... ion_en.pdf
Page 8: Some of the pins inside the module have been pulled or pulled down, please
refer to the schematic diagram
Schematics on Page 13 show RST, EN, GPIO2 and GPIO0 pulled-up; GPIO15 pulled-down. We just need to pull GPIO0 down before power up to enter Download Mode before uploading a sketch with arduino.
Using a CP2102, I've successfully uploaded the Scan and Access Point example sketches as a test.
VCC - VCC
GND - GND
TX - RX
RX - TX
GPIO0 - GND
For Running Mode, I just connected a power supply of 3.3V to Vcc and Gnd to Gnd.