Cactus Micro Rev 2 Details

The rev 2 has four jumpers on the bottom of the board.
R5, R6, J1, and J2 but I can’t figure out what they do from the schematic.
I would love any and all details you can provide.
Are the ESP8266 pins mapped to the arduino pins?
Do the jumpers control this?
It says it has hardwareSerial and softwareSerial what are some situations where I’d choose one over the other?
If I use hardware serial and it’s connected to the Arduino’s hardware serial then does that mean when my android sketch talks to serial it also goes to serial1 on the ESP as well as the computer terminal window?
Also, does that mean when TCP information comes in via the ESP and is routed to the ESP’s serial, that the Arduino can pick it up on serial? or does it have to use serial1?


We have added a Hookup Guide about the pins between ESP8266 and arduino. Please have a look.

The rev2 connect the Serial1 to ESP8266. It have no jumper for change it now. Because the software serial is not stable for Wi-Fi communication.

The Cactus Micro R2 have two hardware serial port – Serial and Serial1. The anduino sketch talks to Serial1 will goes to the ESP.

The new schematic have describe the R5, R6, J1 and J2.

So are R5 and R6 just external pullup resistors?

I’m not sure what the schematic is trying to tell me about the jumpers J1 and J2. Can you explain in words? Do the jumpers map pins on the breakout to different pins on the arduino chip depending on the jumpers?

So from the hookup guide, am I correct to say that there are 4 I/O pins from the ESP8266 mapped to the arduino pins? GPIO0, GPIO12, GPIO13, and GPIO14?


  • J1 will connect ESP GPIO12 to arduino D3 if you short it.
  • J2 will connect ESP GPIO13 to arduino D2 if you short it.

ok thank you for filling in the details. On the schematic on the bottom left there are sets of pins within a square labeled JP1 and then another set of pins in a square labeled JP2…is JP1 and JP2 a set of jumpers as well?

JP1 and JP2 are the pinouts for Cactus Micro R2. I hope the image below helps.