The idea for creating a USB sound card based on a PIC came from discussions of other people creating one on the Microchip USB forum. The hardware of the card is based on all Microchip products. The software uses a modified version of the Microchip USB framework and is interrupt driven instead of the traditional polling. The device is a USB composite device as far as the hardware is concerned. The first device is an implementation of the USB Audio 1.0 interface and the other device is a custom interface based on WinUSB. The purpose of the custom interface is for programming the device serial number, upgrading the firmware, and in the future any other configuration that isn’t supported directly by USB Audio 1.0. The sound card runs at a sample rate of 48KHz, 32KHz or 24KHz selectable by the OS with 12 bits per sample. The quality approaches commercial grade as the sample rate is higher then CDs.
A Microchip PIC based USB sound card – [Link]
The Semtec DP1205 RF module is the core of the modem. This module is a Semtec XE1205 transceiver plus an antenna switch and other required discrete components that are not built on the XE1205 chip. The XE1205 is a very generic 900MHz FM module without any built-in protocol logic. It is very similar to the modules produced by Linx Technologies. The module has an SPI interface for changing between transmitter and receiver modes and for setting the RF frequency and the FM frequency deviation. The data connection directly drives the FSM circuity. For this project, the module uses a 100KHz deviation. The transmission power is 15DBm.
A FCC Legal Frequency Hopping Spread Spectrum USB RF Modem – [Link]
The Message Pump A.K.A. the USB to LCD Backpack is a device that allows you to connect a LCD display directly to your computer. It uses a PIC micro-controller, to drive the LCD and a FTDI USB to serial chip to connect to your computer.
The great thing about the FTDI chip is that it’s drivers are available for Macintosh, Windows, and Linux! The FTDI chip works by creating a VCP (virtual com port) and you may already have these drivers on your computer if you use an Ardunio Diecimila. If not, no worries they are free and and easy install.
Message Pump – USD to LCD - [Link]
Nowadays, USB is the most popular connection connection between PC and peripherals such as AVR programmers, printers, scanners etc. For that reason I had to modify my old serial AVR In-System-Programmer (ISP) to work with USB connection. You can say, “use a USB to Serial adaptor to connect your AVR ISP with your PC”. Yes, that could be a solution but it would cost me more money than a singe FT232BM chip because I had to include an USB to RS232 adaptor and a power supply for my programmer.
USB AVR In-System-Programmer - [Link]
A perfect low cost solution to quickly get screen plots of your GPIB instrument on your laptop PC without complex software. It emulates the HP7470A operation on the GPIB side, and outputs the HPGL data at the USB port to be read and stored on the PC by any capturing software.
Pic-Plot2 : GPIB to USB converter - [Link]
This project is a homebrew 12bit 24KHz homebrew USB soundcard based on a pic18f2550 and a few Microchip analog parts. The project is based on the Microchip USB framework, but the core audio processing is written from scratch. The card is a duel Audio 1.0 + generic interface composite device with the generic interface being handled by WinUSB. The schematic, card firmware, and host C++ software is provided. [via]
USB Audio Streamer : A Microchip PIC based USB sound card – [Link]
This is a simple signal generator which produces sine waves (or any waveform really) at audio frequencies using DDS and is controlled a USB serial connection.Only 2 chips are used in this circuit. The AVR ATmega88 which produces the signal, and an FT232R for the USB interface. While a computer is required to control the varying frequency of the oscillator, a fixed frequency project could be made without the USB interface. [via]
USB controlled DDS signal generator with ATmega88 - [Link]
Looking for compact but flexible, simple and cheap development board? You should consider this nice list of microcontroller USB-Stick tools. These are special development tools that include all necessary hardware and software in a portable USB stick. Most of them consist of two parts – USB stick and attachable target board. [via]
Microcontroller Development tools on USB stick – [Link]
I want to build high quality preamplifier with built-in DAC from SPDIF or USB for my power amplifier Leachamp. I tried to design DAC from USB with this circuit on one-sided PCB and I was successful.
Schematics is from datasheet of PCM2902. Circuit includes DAC and ADC, SPDIF output and input and HID part with 3 buttons for MUTE, VOL+ and VOL-. I used only DAC part. Other parts are not used. For high quality playback is needed to use external low-drop voltage stabiliser for DAC part. I used LP2951CM which was available at local store. Output voltage is set to about 3.7V with two resistors. Circuit board is designed regarding to good ground placement and separating of analog and digital ground. These ground are connected in one point at USB connector. [via]
USB Audio Digital to Analog Converter - [Link]
This project is an instance of the UsbProg project created by Benedikt Sauter. Bene released the schematics, board layout and firmware as an open-source project.The board works when connected to a Win32 PC and with an update to the firmware, enumerates on a Macintosh as well. [via]
UsbProg-SHARP – [Link]