Introducing ESP-01 Module.

There are literally hundreds of posts and forums on introducing and connecting ESP-01 module to computers and program them. I am writing my own version, just to keep note of my own work. I would be glad If it helps somebody to learn and understand this tiny module.

You can refer to post to understand about ESP modules in general. ESP-01 is the first version of module, and I guess this is the most popular of all the versions. The obvious reasons are cost and ease of operation. The module is available in less then 325₹ (~5$) and it can be made operational with some accessories in less then 650₹ (~10$).

The outline of the module is given below. It has 8 pins.

1. 2 power supply pin (VCC & GND).
2. 2 pins for serial transmission (TX & RX).
3. 2 pins for GPIOs ( GPIO0 & GPIO2).
4. 2 Enable and Reset pin (CH_PD & RST).

 ESP-01

At this point, Many folks would be wondering what is GPIOs, Serial transmission, Enable and Reset pins.

In short, GPIOs are General Purpose Input Output – These are standard pins found in almost all micro-controllers. This module has 2 GPIOs, other have many of them. These pins can be made to read input or write (send) output. Same pin can act as both input or output.

Serial transmission is another standard device to device communication protocol, pin TX used for transmission and RX for receiving data. Use wiki to learn more about them.

The Enable and Reset pins are used to make the device operational. CH_PD is kept high for normal operation, this is connected to CHIP_EN of internal chip, it must be kept high to make the chip operational. RST is reset pin, keep it high for normal operation and toggle it high to low to high for hard resetting the module.

GPIO0 decides the mode of operation of the device, at time of reboot (resetting) if the GPIO0 is low, the device enters flashing mode, i.e. new firmware ( code or binary ) can be loaded into the micro controller. when it is high, the device executes existing code. Leave GPIO2 unconnected if you are not using it for I/O.

I can keep on writing how to connect these devices  to computer and program, but it would be too much for one single post. So, I am keeping the connection for the next post.