ESP8266 - Reading the Vcc

This is a quick summary of how to read the Vcc of ESP8266.

Arduino Sketch

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// Source: https://github.com/esp8266/Arduino/issues/3800 ADC_MODE(ADC_VCC); void setup() { Serial.begin(115200); } void loop() { int vcc = ESP.getVcc(); Serial.println(vcc); delay(1000); }

ESP8266 - Getting Chip ID and MAC Address

The code below reads and displays info. such as WiFi MAC Address, Chip ID, Flash Chip ID, Flash Chip Size, etc. about the NodeMCU v1.0 board that I use for making this post.

ESP8266 - Testing the SPI interface using NodeMCU and Arduino Uno

This post is about how to test the SPI interface of ESP8266.

NodeMCU based ESP8266 has Hardware SPI with four pins (D5 ~ D8 in the red square below) available for SPI communication. With this SPI interface, we can connect any SPI enabled device with NodeMCU and make communication possible with it.

ESP8266 has SPI pins (SD1, CMD, SD0, CLK) which are exclusively used for Quad-SPI communication with flash memory on ESP-12E, hence, they can’t be used for SPI applications (the pins in the blue square). We can use Hardware SPI interface for user end applications.

Below figure shows Quad SPI interface pins that are internally used for flash. It consists quad i/o (4-bit data bus) i.e. four (SDIO_DATA0 – SDIO_DATA3) bidirectional (i/p and o/p) data signals with synchronize clock (SDIO_CLK) and chip select pin (SDIO_CMD). It is mostly used to get more bandwidth/throughput than dual i/o (2-bit data bus) interface.

ESP-8266 - Testing out NodeMCU for the first time

Here is a summary of my first experience working with NodeMCU v1.0.

For differences between NodeMCU v0.9 vs v1.0 vs v2.0, refer to the info. at the link below.
https://frightanic.com/iot/comparison-of-esp8266-nodemcu-development-boards/#v1

ESP8266 - compile a custom build NodeMCU for ESP-01

This is a quick summary of how to compile a custom build NodeMCU and the procedure for writing the firmware to ESP-01.

OS used: Windows 8.1

Compile the NodeMCU firmware

This site - https://nodemcu-build.com/index.php is very helpful for building customized NodeMCU firmware. If you find it useful, please make some donation to reward the author and to keep the site running.

For this post, below is the configuration used for making the NodeMCU firmware.