Arduino function for ESP8266

        If programming the GPIO is hard for you as a beginner but you are familiar with Arduino functions, the following functions can be used as have the same name as in the Arduino IDE.

First define some data in an .h file.

#define HIGH 0x1
#define LOW 0x0
#define INPUT 0x1
#define OUTPUT 0x0
                                                   /*   GPIO | SDK board    |       */
                                                   /*   --------------------|       */
int gpio_pin_register[16] = {PERIPHS_IO_MUX_GPIO0_U,    // 0  gpio 0        | 
                             PERIPHS_IO_MUX_U0TXD_U,    // 1  gpio 1        | 
                             PERIPHS_IO_MUX_GPIO2_U,    // 2  gpio 2        | 
                             PERIPHS_IO_MUX_U0RXD_U,    // 3                |
                             PERIPHS_IO_MUX_GPIO4_U,    // 4  gpio 4        | 
                             PERIPHS_IO_MUX_GPIO5_U,    // 5  gpio 5 buzzer | 
                             PERIPHS_IO_MUX_SD_CLK_U,   // 6                |
                             PERIPHS_IO_MUX_SD_DATA0_U, // 7                |
                             PERIPHS_IO_MUX_SD_DATA1_U, // 8                |
                             PERIPHS_IO_MUX_SD_DATA2_U, // 9  gpio 9        | 
                             PERIPHS_IO_MUX_SD_DATA3_U, // 10 gpio 10       | 
                             PERIPHS_IO_MUX_SD_CMD_U,   // 11               |
                             PERIPHS_IO_MUX_MTDI_U,     // 12 gpio12  blue  | 
                             PERIPHS_IO_MUX_MTCK_U,     // 13 gpio13  green | 
                             PERIPHS_IO_MUX_MTMS_U,     // 14 gpio14  white | 
                             PERIPHS_IO_MUX_MTDO_U};    // 15 gpio15  red   | 
                             

#define GPIO_PIN_ADDR(i)    (GPIO_PIN0_ADDRESS + i*4)


Now the Arduino like functions can be added:

/********************************************************************
* FunctionName: pinMode
* Description : set up a pin mode.
* Parameters  : pin: pin mumber
*             : mode 0 for OUTPUT or 1 for INPUT
*             : pullup 0 for pullup DISABLED and 1 for pullup ENABLED
*             : pulldown not yet supported
* Returns     : None                                                     
*********************************************************************/

void ICACHE_FLASH_ATTR pinMode(uint8_t pin, uint8_t mode, uint8_t pullup) {
    if ((0x1 << pin) & 0b110101) {
        PIN_FUNC_SELECT(gpio_pin_register[pin], 0); //0,2,4,5
    } else {
        PIN_FUNC_SELECT(gpio_pin_register[pin], 3);
    }
    PIN_PULLDWN_DIS(gpio_pin_register[pin]);
    if(pullup)
      PIN_PULLUP_EN(gpio_pin_register[pin]);
    else  
      PIN_PULLUP_DIS(gpio_pin_register[pin]);
    if (mode) {
        GPIO_REG_WRITE(GPIO_ENABLE_W1TC_ADDRESS, 1<<pin); // GPIO input
    } else {
        GPIO_REG_WRITE(GPIO_ENABLE_W1TS_ADDRESS, 1<<pin); // GPIO output
    }
}


Example:
pinMode(0, OUTPUT, 0); //is setting the GPIO 0 as an OUTPUT with pullup disabled

If you want to control also the pulldown add an extra parameter and call the 
PIN_PULLDWN_DIS(gpio_pin_register[pin])for disable and PIN_PULLDWN_EN(gpio_pin_register[pin])for pulldown enable.


Next function are the well known Arduino function for read and write:

/********************************************************************
* FunctionName: digitalWrite
* Description : use to set up HIGH or LOW on a GPIO pin
* Parameters  : pin: pin mumber
*             : state HIGH or LOW
* Returns     : None                                                     
*********************************************************************/

void ICACHE_FLASH_ATTR 
digitalWrite(uint8_t pin, uint8_t state) {
    if (state) {
        GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, 1<<pin); // set GPIO pin high
    } else {
        GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, 1<<pin); // set GPIO pin low
    }
}
/********************************************************************
* FunctionName: digitalRead
* Description : use to set up HIGH or LOW on a GPIO pin
* Parameters  : pin: pin mumber
* Returns     : 1 if pin is HIGH or 0 if pin is LOW                                                     
*********************************************************************/

int ICACHE_FLASH_ATTR 
digitalRead(uint8_t pin) {
    return (GPIO_REG_READ(GPIO_OUT_ADDRESS)>>pin) & 1;
}



Example:

digitalWrite(0, HIGH); //set HIGH the GPIO 0 pin

int gpio_state = digitalRead(0); will return 1 if the GPIO 0 pin's is HIGH or 0 if is LOW

If you save your .h file in the include directory, just use #include "your_file_name.h" in your user_main.c.


For controlling GPIO16 see this post.

Making your own environment for ESP8266.

If you don't want to use my setup described here, you can make your own setup using your own distribution.

You can make your own environment for compiling your code or the demo code for the ESP8266.

Step 1.

Download ova image  ( lunbuntu 14.04) for VirtualBox or install your preferred Linux distribution.

User is esp8266 and password is  espressif

sudo apt-get install git autoconf build-essential gperf bison flex texinfo libtool libncurses5-dev 

wget gawk libc6-dev python-serial libexpat1-dev

Step 2.

sudo mkdir /opt/Espressif

Step 3.

sudo chown esp8266 /opt/Espressif/

Step 4.

cd /opt/Espressif

Step 5.

git clone -b lx106 git://github.com/jcmvbkbc/crosstool-NG.git

Step 6.

cd crosstool-NG/

./bootstrap && ./configure --prefix=`pwd` && make && make install

Step 7.

./ct-ng xtensa-lx106-elf

Step 8.

./ct-ng build

Note: It takes about 25 minutes !!!!!!!

Step 9.

Edit the .profile file from /home/esp8266 and add the line

PATH="$HOME/bin:/opt/Espressif/crosstool-NG/builds/xtensa-lx106-elf/bin:$PATH"

Step 10.

cd /opt/Espressif

wget -O esp_iot_sdk_v0.9.5_15_01_23.zip https://github.com/esp8266/esp8266-

wiki/raw/master/sdk/esp_iot_sdk_v0.9.5_15_01_23.zip

Note: is the SDK from 23 Jan 2015. Verify if there is a new one.

Step 11.

unzip esp_iot_sdk_v0.9.5_15_01_23.zip 

mv esp_iot_sdk_v0.9.5 ESP8266_SDK/

Step 12.

cd /opt/Espressif/ESP8266_SDK

wget -O lib/libc.a https://github.com/esp8266/esp8266-wiki/raw/master/libs/libc.a

wget -O lib/libhal.a https://github.com/esp8266/esp8266-wiki/raw/master/libs/libhal.a

wget -O include.tgz https://github.com/esp8266/esp8266-wiki/raw/master/include.tgz

tar -xvzf include.tgz

rm include.tgz

Step 13.

cd /opt/Espressif

git clone https://github.com/themadinventor/esptool esptool-py

chown -R esp8266 crosstool-NG/

sudo ln -s $PWD/esptool-py/esptool.py crosstool-NG/builds/xtensa-lx106-elf/bin/

Step 14.

The SDK esp_iot_sdk_v0.9.5_15_01_23.zip has a directory named Document with some pdf files about API, AT commands and release notes.

Step 15. 

Copy the "at" directory from /opt/Espressif/ESP8266_SDK/examples and compile it

cp -R /opt/Espressif/ESP8266_SDK/examples/at /opt/Espressif/ESP8266_SDK/

cd /opt/Espressif/ESP8266_SDK/at

make clean

make 

The result resides in the /opt/Espressif/ESP8266_SDK/bin directory

Flashing the code. Note that the above command is on long line. You can put the command into a file flashEsp, give that file executable rights and use it with ./flashEsp

sudo /opt/Espressif/esptool-py/esptool.py --port /dev/ttyUSB0 write_flash 0x3C000 /opt/Espressif/ESP8266_SDK/bin/blank.bin 0x00000 /opt/Espressif/ESP8266_SDK/bin/eagle.flash.bin 0x40000 /opt/Espressif/ESP8266_SDK/bin/eagle.irom0text.bin OR /opt/Espressif/esptool-py/esptool.py -p /dev/ttyUSB0 write_flash 0x40000 ../bin/eagle.irom0text.bin write_flash 0x00000 ../bin/eagle.flash.bin


I hope I didn't missed any step.

Use my ESP8266 environment !!!

User ESP8266
password espressif

Let's see how you can compile our first example of code.

To do this download the virtual box ova from my drive.

Apply this ova file to a Virtual Box.

Start the virtual machine

go to /opt/Espressif/ESP8266_SDK/ where there are two directories with examples:

IoTDemo - a web server controlling  some GPIO's
at - build a custom AT command along with all command that are supportded by the at library


go to /opt/Espressif/ESP8266_SDK/IoTDemo/
make clean
make

two files are generated into the /opt/Espressif/ESP8266_SDK/bin directory.
!!!
No boot needed.
Generate eagle.flash.bin and eagle.irom0text.bin successully in folder bin.
eagle.flash.bin-------->0x00000
eagle.irom0text.bin---->0x40000
!!!

 Use those files and the optional blank image blank.bin or you can use this command
to write the files.

sudo /opt/Espressif/esptool-py/esptool.py --port /dev/ttyUSB0 write_flash 0x3C000 /opt/Espressif/ESP8266_SDK/bin/blank.bin 0x00000 /opt/Espressif/ESP8266_SDK/bin/eagle.flash.bin 0x40000 /opt/Espressif/ESP8266_SDK/bin/
eagle.irom0text.bin

Write the files on ESP-01.
1. Power off the ESP-01
2. Connect GPIO0 to GND
3. Power on the ESP-01
4. Burn firmware

Write the files on ESP201 Dev Board.
1. Power off the ESP-201
2. Keep pressed S2 and power the board
3. Release the S2 switch
4. Burn firmware

Notes:

1. In /opt/Espressif/ESP8266_SDK/document/ there are tow directories English an Chinese with document about the SDK fucntion, AT command. Spend some time looking into them.
2. In the Virtual Box image I've added the moserial application that can be used to see the debug information from ESP.
3. Launch moserial with: sudo moserial &
4. If Software Updater is bugging you, do not update. You are just fine.