Goldilocks Analogue

Finally finished all of the testing and development.

Aside from a hick-up caused by an incorrect Eagle footprint everything tested as designed.

Launched a Goldilocks Analogue - Kickstarter Project to encourage others to dive into the audio and analogue world with a Arduino.

Please, back this project if you can.

The SPI bus on the Arduino platform (including the Goldilocks Analogue) is overloaded with activities. Driving the uSD card requires tying up the bus for many hundreds of milliseconds, and this conflicts with the need to output regular audio samples.

Moving the DAC to the spare USART1 on the ATmega1284p MCU was the best answer.

Using Master SPI Mode on an ATmega USART

Most of the analogue section was working correctly, but there are some additional features that are needed, such as SPI storage using EEPROM, or SRAM, and modifying the way that the DAC is driven.

Prototyping - Version 3

It is convenient to have a simple file system for use on the SPI EEPROM or RAM, to allow a number of wave tables, WAV files, or other files to be assembled on a host and then written to the EEPROM as one file.

The NASA developed EEFS is a good solution for this need, but it was developed with 32 bit machines in mind. The AVR ATmega uses 16 bit pointers, and so there needed to be some changes.

Implementing NASA EEFS on AVR ATmega

Testing against the Open Music Labs Audio Codec Shield

Testing against the Stanford TI Analog Shield

Design for Second Prototype

Prototype 1 - Testing

Design - Part 1