Software serial uses timer, be careful when you are using software serial. Timer is also used for WiFi communication section if you don’t give enough time to WiFi routines it will create problem of stack error or misbehavior. It is better to use software serial only when you need two serial ports and also avoid use of software serial for data reception.
Tag Archives: ESP8266
IO Level Conversion 3.3V to 5V for ESP8266
Most cases we need to interface 5V (TTL) logic level devices with ESP8266. For this you can simple use 1N4148 diode and one pull-up resistor.
The above circuit working can be understood using below figure.
- When we give logic 1 i.e. 5V to TXD diode becomes reverse bias and ESP 3.3V RXD pin gets supply of 3.3V (Logic 1) from pull-up.
- When we give logic low 0V to TXD pin the diode becomes forward bias and the voltage at its anode terminal drops below 0.7V i.e. logic zero.
- For TXD pin of ESP we don’t need any circuit as we can read 3.3V as logic 1 and 0V as logic 0 using any 5V controller.
5V TTL Serial Communication with ESP8266
For serial interface you have two options go with 3.3V USB to Serial converter or use above circuit to do level conversion and use 5V serial converter.
Serial interface is required to program the ESP flash.
Reset and Programming Circuit of ESP8266
ESP8266 require a sequence of input to enter into programming mode when programming is done using Arduino IDE. With few external components.
Power supply Design for ESP8266
ESP8266 operates at 3.3V and consumes around 100mAmp current, for designing of its power supply you can use LM1117-3.3V Low drop out (LDO) linear regulator which is having current capacity of 800mAmp. Remember that, this regulator is low drop out regulator. It is better to give 5V as input to the regulator to avoid over heating of regulator. You can create small heat sink on PCB using copper area.
ESP8266 Pin Diagram
ESP8266EX is among the most integrated WiFi chip in the industry; it integrates the antenna switches, RF balun, power amplifier, low noise receive amplifier, filters, power management modules, it requires minimal external circuitry, and the entire solution, including front-end module, is designed to occupy minimal PCB area. ESP8266EX also integrates an enhanced version of Tensilica’s L106 Diamond series 32-bit processor, with on-chip SRAM, besides the WiFi functionalities. ESP8266EX is often integrated with external sensors and other application specific devices through its GPIOs; sample codes for such applications are provided in the software development kit (SDK).