Introduction
This module was developed to allow me to play MP3 songs though my existing Toyota car audio system, in my case a stock standard Toyota branded TST-5170, this uses the Toyota proprietary protocol based around the IEBus physical layer.
The project was inspired by the Toyota corolla MP3 project the project and combined with software collected from a variety of different sources and combined together by myself.
The heart of the hardware is based on two Atmega MCU’s with data storage on a standard FAT formated SD card, which contains the MP3 tracks. One of the MCU’s, the Atmega 8 takes care of encoding and decoding the AV-LAN data while the other reads the SD card and drives the VS1011 a very common MP3 decoder ASIC.
The circuit to interface to the IE bus is undertaken using a comparator to convert the differential mode signalling to single ended, comms, again this was based on the Toyota corolla MP3 project mentioned above.
Downloads
Schematic