How to program ESP01S - Erratums/ESP8266 GitHub Wiki

About ESP01 programmer

Most of the ESP01 programmer is using CH3x IC. You need to install additional driver for this. Download CH3x driver
1 main difference between the ESP01 and ESP01S is that, we need an additional 10K pull-up resistor for ESP01 to enable it [for CH_PD]. So if you are programming ESP01 then you need to solder extra pull-up resistor. [If you buy from our sore, this is pre-soldered]
The programmer designed for ESP01S won't have this pull-up resistor. So we need to solder it. [10K resistor b/w CH_PD and 3.3v]
The above device has 2 modes which can be adjusted using the slide switch
- Programming Mode
- Development Mode
Note: The GPIO0 of ESP01 should be pulled low to enter to program mode. This is what the switch on the programmer is doing. So if you want to program ESP01 again, remove the programmer from USB and re-plug it. If you try to program continuously without re-plugging the programmer, you cannot upload the code

If you don't know how to install ESP8266 into Arduino IDE, please refer this link
How to install ESP8266 in Arduino

Once the driver software is installed properly, plug the esp01s to programmer
Slide the switch to prog mode
Connect the programmer to USB
If the driver is installed properly, your computer detect USB device. You can see this USB listed in the ports
Select this port
Then select the Generic ESP8266 Module from the Board Manager as shown below
Your settings should look like this. [Port might be different in your computer]
Now upload the code