When I first got introduced to the world of the ESP8266, I had a real hard time to find a way to flash the firmware of the ESP826601 with an Arduino Uno. How to Directly Program an Inexpensive ESP8. Wi. Fi Module. The ESP8. I want something with Wifi. Surprisingly, there are a number of engineers and hobbyists who have not heard of this chip or have heard of it but dont really understand what it is. Its basically the answer to everything Io. T to so many engineering problems that have plagued the hobbyist and commercial world alike. Plotting LM35 temperature data on ThingSpeak with an Arduino and ESP8266 WiFi module. The chip is a processor with integrated RAM, some ROM, and a Wi. Fi radio, and the only external components you will need are 4 capacitors, a crystal and an external flash Its CHEAP, like 4ea cheap Or 5 if you want it on a nice, convenient carrier board that includes all these components. The power consumption is reasonable 2. A1, the range is insane 3. Magix Foto Clinic 5.5 here. PCB trace antenna and 4km if you want to be ridiculous. One place thing that more people need to know about is how to program directly for this chip. Too many times projects use it as a crutch via the AT commands. Read on and find out how to hello world with just this chip. Know thy Hardware. First off, some background. Lets start with a picture of it decapped by zeptobars, and marked up by swimmmerdude. The processor by default runs at 8. MHz but can go up to 1. MHz, it has 8. 0k. B DRAM Data RAM, and 3. B of high speed IRAM Instruction RAM. Yes, that means it uses a Harvard architecture. The IRAM is loaded at boot with whatever the user wants to keep on processor, though the processor can run code directly off of the external flash at a lower speed. Firmware Background. By default when you buy these neat little boards, many of them come with the AT firmware, which is basically a really neat, easy, tool that lets you use these devices as simple wireless modems controlled through a serial port. Thats neat and all, but it is difficult to do particularly complicated things with this and as I mentioned before it requires the use of an external processor. Two different ESP8. There are a few modes the chip can boot in based on the configuration of some GPIO pins. We wont be discussing SDCard startup as most of the hobbyist community has not really taken to it, but we will be discussing Flash startup and UART download. Additionally, there is a remote firmware upload feature that has a few different revisions and possibilities, but well save that for another post. For the two modes we care about, the processor expects GPIO1. GPIO2 to be high on boot. GPIO0 selects between the two modes we are going to discuss here. During normal operation, we would want to use a resistor to pull GPIO0 high. That will cause the bootloader inside the ESP8. EEPROM chip into the ESP8. IRAM and boot our program. If we set GPIO0 low, however, the boot ROM inside the ESP8. UART. Using this boot ROM we can push our programs to the flash memory. A good way to make use of this is to connect a switch from GPIO0 to ground so you can put it into program mode at will by holding the button at power on. This is surprisingly reliable and even supports different baud rates. I use 4. 54,8. 00 for my baud rate, so I can make modifications to my programs and test them very quickly. One of my projects takes less than a second to compile and about 8 seconds to burn. There are official tools to upload firmware XTCOM, however I personally like to use esptool. Additionally, once it finishes flashing the chip, even if GPIO0 is tied low, it will cause your firmware to run. Then, if your code reboots, it will automatically re enter the bootloader for another programming cycle. This means you can keep GPIO0 hooked to GND while youre developing. All in all, our development tools look like A switch from GPIO0 to ground with a pull up resistor to VCCGPIO2 and CHPD connected to VCCGPIO1. USB to TTL UART Adapter communicating with ESP8. V to the 3. 3. V regulator powering the chip. Btw you can get USB to TTL level UARTs super cheap, check out electrodragon for ones that are less than 1ea Toolchains. Programming the ESP8. There are a few options for building the toolchain on Linux and OSX, plus some options in Windows. Ive tried to keep a list of toolchains in my ws. Details about building the toolchain are outside of the scope of this how to but follow that guide, or this possibly more up to date toolchain tutorial, and you should have no issues. Once you get a toolchain built and you can compile a firmware, like my WS2. ESP8. 26. 6 firmware, youll be good to go for the rest of this article. Espressif has been nice enough to distribute their SDK freely. This was something that absolutely shocked the community, in a good way This was extremely generous and a move few companies make. The SDK contains an example, and headers for the ROM as well as Espressifs library. Its important to note that there is a community library, but every time Ive used it so far it does not match the same level of maturity as the espressif library. Perhaps thatll change in the future. Be sure to check out the include folder in their SDK. This includes a lot of awesome functions to help get you from zero to hero in no timeProgramming Theres a ROM for That. Theres a few things to take note of when programming the ESP8. One is that there are a bunch of functions that are built into the ROM you can leverage. This means you dont need to and shouldnt re implement MD5 even with hmac, SHA1, comms with the external flash, SPI, UART functions, software floating point functions, AES, memory commands, printf, low level IO tools, even a real time event scheduler, and, most importantly 8. The full list of functions that reside in the on chip ROM can be found in eagle. It would behoove you to take a look in there now and see the wonderland of awesome thats provided out of the box. In addition to the on chip ROM, theres more to their API that sits on top to make using this thing as easy as pie. We can see a number of facilitating tools. Because the ESP8. Ive never tried, it has a number of tools you can use. By default the ESP8. AP. I. e. when you power it on out of box and start their API, it starts in host mode running its own DHCP server. You can find it by looking for a wifi network that starts with ESP8. Embrace Abstraction. If youre looking to write main and have your own main loop, thats not going to happen. While you can write main, the API expects to have its own main loop. In this sense, programming the ESP8. Arduino. static void ICACHEFLASHATTR proc. Taskoseventt events. Task. Prio, 0, 0. Idle Taskn. void userinitvoid. Task, proc. Task. Prio, proc. Task. Queue, proc. Task. Queue. Len. systemospostproc. Task. Prio, 0, 0. If you need events to happen at regular intervals, there are timer functions, ostimersetfn, ostimerarm that can call a function at a specific interval. Thats great for the overall environment, however, we havent actually talked about how to do anything with this part. Vector Graphics Software Mac Os'>Vector Graphics Software Mac Os. Lets talk about how to use 8. If youre afraid, I dont blame you. Install Grub2 On Usb Drive From Windows. Trying to change 8. Ever try doing it in Linux or Windows programatically Its terrifying. On the ESP8. Connect ESP8. AP in 8 lines of Code. Once your ESP8. 26. Conf. wifisetopmode STATIONMODE. Conf. ssid, ssid, 3. Conf. password, password, 3. Conf. wifistationconnect. No, really, its just that easy. Itll just connect to your AP, pull an IP and sit there. No fuss no muss. On top of that, itll remember this operation and next time you boot it, itll connect right up.