You need a USB to serial device that can output data at 3v3 volt or you have to use with a level converter (I'm actually using a cheap chinese unit with a 4050 chip), DTR or whatever are not so essential, only TX and RX.
You also need a strong 3v3 supply, the ESP8266 suck a lot of current and will not work if supply it's not consistant!
The ESP8266 connections, depends of module you have, if you use the cheap standard one (GPIO0 and GPIO2):
TX -> usb to serial RX
RX -> usb to serial TX
GND -> GND
+3v3 -> +3v3 (with at list 500/600ma)
ChPD -> +3v3
RST -> +3v3
GPIO2 -> +3v3
GPIO0 -> GND (when you program the chip), +3v3 (normal operation) Switching between modes require a Hardware reset.
Other ESP modules with GPIO15 or similar have a slight differences caused by extra GPIO's, you'l need to check forum for that.
About software, you need to install Python 2.7.
http://python.org/, it should be installed correctly and should work at system level.
Download esptool.py
https://github.com/themadinventor/esptool/raw/master/esptool.py, create a folder in C: and put esptool.py inside.
Download firmware
https://github.com/espressif/esp8266_at/tree/master/bin and put files in the folder you have created.
Now you need the CMD shell, type CMD in windows run.
You need to point the shell in the directory you have created before, use command CD until you are there.
You also need to find out the COM your USB to serial it's using, let's say COM15 (as example)
Now time to type something on shell (one by one):
Code:
esptool.py -p COM15 write_flash 0x00000 boot_v1.1.bin [enter]
..If succesfully, reset ESP to prepare it to accept another upload
Code:
esptool.py -p COM15 write_flash 0x01000 user1.bin [enter]
..If succesfully, reset ESP to prepare it to accept another upload
Code:
esptool.py -p COM15 write_flash 0x7C000 esp_init_data_default.bin [enter]
..If succesfully, reset ESP to prepare it to accept another upload
Code:
esptool.py -p COM15 write_flash 0x7E000 blank.bin [enter]
Done. If you don't close the CMD you can disconnect power to esp, connect another one and instead retype everithing you just use the up/down arrow and repeat sequence.
Looks complicated but at the end it's not really. If you have troubles don't esitate to contact me.
Use it... Can be used in many ways, direct AT commands, using Arduino modified IDE to install a dedicated program and work as standalone or using UART with Teensy or use nodeMCU.
If you download ESPlorer
http://esp8266.ru/esplorer/ you can play with it since it's still connected with USB to serial and check everithing works.
If you plan to use the Arduino modified IDE from ESP8266 forum on windows, unfortunatly they don't upgraded the win distro often so I had to recompile the IDE myself to have the whole thing really working (the one online it's not working almost at all on WIN).
If you need I can put the IDE somewhere and provide the link, the last version can overclock the ESP at 150Mhz as well and I've succesfully used for install REST and standalone server that communicate by serial with Teensy, it's like to have a kinda YUN for 2,5 buks!
PS
You do a great work with your mini modules, really amazing design!