2020/12/31

How to use / navigate this blog

This is a quick summary of how to use / navigate this blog.

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2017/10/18

ESP8266 OTA - OTA over internet using HTTP server

This post is about how to perform OTA over the internet. The firmware to be downloaded and install on ESP8266 via OTA is stored on a HTTP server.

The hardware used for this post is NodeMCU v1.0.

2017/10/07

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.

2017/10/03

Raspberry Pi - How to check whether PHP is installed and its version

This is a quick summary of how to check whether PHP is installed and its version.

1. Login to your Raspberry Pi.

2. Change the working directory to "/var/www/html".

2017/10/01

About Arduino Ethernet Shield v1 and Arduino Ethernet Shield v2

This post is a quick overview of Arduino Ethernet Shield v1 and Arduino Ethernet Shield v2.

Arduino Ethernet Shield v1

Source: https://www.arduino.cc/en/Main/ArduinoEthernetShieldV1


Ethernet Controller: Wiznet W5100 with internal 16K buffer

Interface to Arduino: Arduino communicates with both the W5500 and SD card using the SPI bus (through the ICSP header). This is on digital pins 10, 11, 12, and 13 on the Uno and pins 50, 51, and 52 on the Mega. On both boards, pin 10 is used to select the W5500 and pin 4 for the SD card.

Arduino Library: Ethernet.h

Production Status: this product is currently retired and the documentation will not be kept up-to-date

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Arduino Ethernet Shield v2

Source: https://www.arduino.cc/en/Main/ArduinoEthernetShieldV2


Ethernet Controller: Wiznet W5500 with internal 32K buffer

Interface to Arduino: Arduino communicates with both the W5500 and SD card using the SPI bus (through the ICSP header). This is on digital pins 10, 11, 12, and 13 on the Uno and pins 50, 51, and 52 on the Mega. On both boards, pin 10 is used to select the W5500 and pin 4 for the SD card.

Arduino Library: Ethernet2.h

Production Status: In production.

2017/09/26

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.