For users of advance MCUs like the XMega it is not necessary to tell what an analog-to-digital converter (ADC) is or what it does. I assume this is not the first family of microcontroller they are dealing with. Unlike the ADCs of other microcontroller the ADC of XMega devices is a highly complex tool. The level of complexity is so much that without understanding every bits-and-pieces of this piece of hardware a user won’t enjoy its absolute power. XMega ADC is also the most confusing hardware as it is not like other MCU ADCs. We will be dealing with ATXMega32A4U and it has only one ADC block, named ADCA but some other XMega devices like the XMega128A1 have more than one ADC block – ADCA and ADCB. By the way the XMega reference manual provides a long literature on the ADC and I’m not willing to state everything.
A quick view of the ADC block diagram shows most of the internal arrangement.
With so many other development platforms already out there in market, DSP Robotics, in collaboration with MikroElektronika, is going to introduce a new tool, FlowPaw, for rapid prototyping with electronics and robotics. FlowPaw is an expandable development board that carries a STM32F415RG MCU and four mikroBUS™ sockets, which provides a simple Plug-and-Play solution for connecting mikroElektronika’s several dozens of accessory boards called Click Boards. The Click boards are available for a wide range of applications including GPS, WiFi, MP3 decoding, Bluetooth, CAN, IrDA, GSM, and Ethernet. The FlowPaw is programmed directly through a PC USB port using FlowStone, a drag-and-drop programming tool. For those who are interested in getting a first-hand experience with FlowPaw, DSP Robitics is currently running a crowdfunding campaign over Kickstarter.
FlowPaw main board
In Part 1 of this project, we described the construction of Easy Matrix, which is a cascadable 8×8 LED matrix display with MAX7219 chip on board. We developed an Arduino sketch for scrolling text display, whereby the Arduino receives text messages from its serial port and displays the message on a 8×40 LED matrix constructed by daisy-chaining five Easy Matrix modules. The Arduino firmware is also capable of receiving user commands for controlling the scrolling speed and brightness level of the display. In this part, we will discuss about extending the project to cascade 8 Easy Matrix modules and control the display over a Bluetooth connection.
My 3 year old son using the display as a tool for learning alphabets and numbers
LED matrix displays are great fun. They are visually charming, and readable from a far viewing distance with a much wider angle of view as compared to many other types of electronics displays. They can display all kinds of information, including text, graphics, and animation. This project is about making a portable Bluetooth-controlled 8×64 monochromatic LED matrix (total 512 LEDs) for displaying scrolling text message. I made this display to use at home parties or other occasions for displaying greeting messages. The text data to be displayed can be sent from a smartphone using the Bluetooth connection. The display is Arduino-controlled and uses the HC-06 Slave Bluetooth transceiver module for receiving data from the smartphone. I am also using the Bluetooth SPP Pro (freely downloadable) App (developed by Jerry.Li) on my HTC One Android smartphone for sending text message to the matrix display. The complete project has got a nice enclosure made by myself using furring strip boards bought from the Home Depot. We looked at a similar project earlier made by Jollyfactory, who used bi-color LED matrices, which required two MAX7219 devices per 8×8 matrix.
Bluetooth-enabled scrolling LED matrix display
Delay effects are commonly implemented in various audio systems including Karaoke player, guitar amplifier, advanced sound processing equipment, recording studios, television etc. It basically adds an echo to the original audio by repeating the audio after a specified amount of time. Rajkumar Sharma’s new project is about building an echo generator using Holtek’s HT8970 IC, which is an echo/surround effect processor with built-in pre-amplifier, VCO, 20Kb SRAM, A/D and D/A converters as well as delay time control logic. With all these functions built inside the chip, you can easily enhance your audio with an echo effect using a minimal number of external components.