Definitions

Dimension

  • pitch 2.0 mm
  • width 16 mm

ref

  • legacy chip wiki page here - https://w.electrodragon.com/w/Category:ESP8266
  • legacy module page - https://w.electrodragon.com/w/ESP-12F_ESP8266_Wifi_Board

Internal SCH

Pin Definitions

left right func
RST external pull-up, with cap TXD    
ADC   RXD    
EN external pull-up IO5    
IO16   IO4    
IO14   IO0 external pull-up mode select
IO12   IO2 external pull-up  
IO13   IO15 external pull-down  
VCC   GND    
  • on module LED IO2: low to on

Periperhal design

datasheet