![\"\"](\"http:\/\/wp.spoton.cz\/wp-content\/uploads\/2017\/11\/20171121_141843.jpg\")
<\/a><\/p>\n<\/p>\n
First the pins and what they mean:<\/p>\n
- \n
- TX<\/strong> – Transfer, serial send pin<\/li>\n
- EN<\/strong> – ENABLE, or SELECT, or… it has multiple names. This pin needs to be set high (read logical 1 – ~3 – 3.3V) for the module to work, send and receive data. Putting it high with Vcc \/ Vin throgh a resistor or directly is a good idea<\/li>\n
- RST<\/strong> – RESET. We’re going to use this one. If set LOW, device reset is initiated, but for the device to boot and actually reset, you must take the GND off this pin. In normal operation this should be set HIGH. Leaving it “in the air” is not a good idea.<\/li>\n
- 3V3<\/strong> – Vcc \/ Vin – call it as you like – Input voltage. Mind you, 3.3V max!<\/li>\n
- GND<\/strong> – GROUND. doh!<\/li>\n
- IO2<\/strong> – General purpose I\/O pin #2<\/li>\n
- IO0<\/strong> – General purpose I\/O pin #0, we’ll need this one for flashing as well<\/li>\n
- RX<\/strong> – Receive, serial receive pin<\/li>\n<\/ul>\n
If you are using an FTDI programmer, USB dongle, or other interface, make sure it is 3.3V capable. If you start chucking 5V signals at it, it misbehaves. People have reported the ESP8266 to be 5V tolerant, but I found it far less stable at 5V logical levels. And how long it takes to get damaged at that rate? Who knows.<\/p>\n
Pay the extra buck and get one of these (switchable 5V \/ 3.3V logic):<\/p>\n
![\"\"](\"http:\/\/wp.spoton.cz\/wp-content\/uploads\/2017\/11\/20171121_142232-1024x444.jpg\")
<\/a><\/p>\nFor sheer lack of due diligence, I had to use an Arduino Nano as a voltage stabilizer. Please don’t do this, it is utter nonsense. I know however, that for testing purposes and flashing, the current supplied by the Nano is sufficient, so, leave me alone with this.<\/p>\n
![\"\"](\"http:\/\/wp.spoton.cz\/wp-content\/uploads\/2017\/11\/20171121_142303-1024x741.jpg\")
<\/a><\/p>\nYou should however think about using one of these (at least) for voltage stabilization:<\/p>\n
![\"\"](\"http:\/\/wp.spoton.cz\/wp-content\/uploads\/2017\/11\/20171121_150124-1-1024x627.jpg\")
<\/a><\/p>\nThis power supply is cheap, tolerant to 5V-12V (some say 24V is OK – gonna test it :-)) and has 4 pinouts, so can power 4 arduinos.<\/p>\n
Connect like this. If you are not lazy, nor stupid, don’t use the arduino as a voltage regulator. \ud83d\ude09<\/p>\n
![\"\"](\"http:\/\/wp.spoton.cz\/wp-content\/uploads\/2017\/11\/8266_schema-1024x724.png\")
<\/a><\/p>\nThe pain of finding out how<\/h2>\n
I thought, that there is only one firmware, and only one way to do things with the ESP-01s. Turns out, there are multiple firmwares available, AT commands, Python derivates… ehm, let’s concentrate on how to bring the ESP back to factory (AT firmware) setup. Great resource for FWs and documentation, of course:\u00a0http:\/\/esp8266.net\/<\/a>.<\/p>\n
How to flash<\/h3>\n
You need PYTHON installed. Flash software:\u00a0https:\/\/github.com\/espressif\/esptool<\/a>\u00a0– I like to use GIT, so:<\/p>\n
https:\/\/github.com\/espressif\/esptool\ncd .\/esptool\/<\/pre>\n
The basic commands to flash a .bin file is as follows (Don’t forget to set up correct privileges – i.e. add yourself to “dialout” group or – use sudo).<\/p>\n
sudo .\/esptool.py --port \/dev\/ttyUSB2 write_flash 0xFE000 .\/ESP8266_AT\/bin\/blank.bin \nesptool.py v2.2-dev\nConnecting........_\nDetecting chip type... ESP8266\nChip is ESP8266EX\nUploading stub...\nRunning stub...\nStub running...\nConfiguring flash size...\nAuto-detected Flash size: 1MB\nCompressed 4096 bytes to 26...\nWrote 4096 bytes (26 compressed) at 0x000fe000 in 0.0 seconds (effective 4743.5 kbit\/s)...\nHash of data verified.<\/pre>\n
Now that we know how to destroy things, write crap to the controller, let’s do something useful…<\/p>\n
Gather the firmware!<\/h3>\n
AT firmware:\u00a0https:\/\/github.com\/espressif\/ESP8266_AT\/tree\/master\/bin<\/a>\u00a0– this is stock, AT firmware, that came with the ESP-01s preinstalled. I want that!<\/p>\n
git clone https:\/\/github.com\/espressif\/ESP8266_AT<\/pre>\n
It says to flash these bins to the specified address (which I later found out it is wrong on my ESP).<\/p>\n
Bin Address\nboot_v1.1.bin---------------->0x00000 (reset)\nuser1.bin-------------------->0x01000 (reset)\nesp_init_data_default.bin---->0x7C000 (no reset)\nblank.bin-------------------->0x7E000 (reset)\n\n<\/pre>\n
Let’s see… (how to observe ESP8266 boot sequence? later! Just take it as a fact, read on)<\/p>\n
...\nSPI Speed : 40MHz\nSPI Mode : QIO\nSPI Flash Size : 8Mbit\njump to run usererror user bin flag, flag = 6\nuser code done<\/pre>\n
Nope. Dead. A spark of hope though, this clearly shows, that it is not fried, just misconfigured somehow.<\/p>\n
The way I read the documentation, there is a boot code and a user code (more on the boot later on). The user code should contain the AT commands functionality, but here it seems it doesn’t even run, or errors out. Might this be a problem of a mis-fired, wrongly placed user.bin?<\/p>\n
Go back in line, repeat again<\/h3>\n
- EN<\/strong> – ENABLE, or SELECT, or… it has multiple names. This pin needs to be set high (read logical 1 – ~3 – 3.3V) for the module to work, send and receive data. Putting it high with Vcc \/ Vin throgh a resistor or directly is a good idea<\/li>\n