• Siemens / Infineon 80C161-RI-LM-16MHz-TQFP100
  This CPU supports an addressregion of 16 MB spread over 5 chip-select-signals, three different serial interfaces: 1x asynchron serial, 1x synchron serial and 2 IIC channels, 11 GPIO for interrupts (in a sum the CPU supports 76 GPIO-pins!), 5 inputs with a sample&hold analog to digital converter, 8 PEC-transferstages (something like a DMA-channel), 5 timer-units, and 32 interrupt-priority-levels.
  I have choosen this CPU because of the 16-bit databus which can directly connected to the 16-bit harddisk interface. Yet, I don't know all other features of the CPU, but even when I figure out more and more the CPU becomes very comfortable! Not easy to beginn with, but at the end I can say that it is worth to work with this controller!
  
• VLSI VS1001-K
  This IC does the most decoding part. It is a real MP3-Decoding IC with 2 digital SPI-interfaces (data and control) and in fact an analog stereo audio output - able to drive a 30 Ohm speaker. The VS1001 is driven by a 24.576 MHz oscillator and decodes an input stream with constant or variable bitrate up to 320kBits/sec.This IC works between 2.5V-3.6V.
  
• 128KB SRAM and 512KB Flash-ROM
  I have connected a 64K x16 SRAM with 15ns to prevent unnecessary waitstates and a 512K x8 Flash ROM which is easy and cheap to find - a smaller one could fit also!
  
• 2.5" Harddisk
  I am using a common laptop harddisk which runs with 5V at a maximum power consumption of 500mA. The harddisk can store 3 GB data on a Windows FAT32-compatible logical partition. The harddisk is directly connected to the 16-bit databus. In conjunction with the PALCE22V10 the circuit supports a ATA/IDE-compatible interface.
  
• Bootstrap- and Debug-Interface
  The asyncrhon serial interface is converted by a Maxim MAX232 and supports up to 38400 Baud. Over this line the bootstrapping is done - even if I want to debug a new SW-version running from RAM.
• Keypad and Display
  A common LC-display is also connected at the low 8 bits of the databus. It is a 16x2 character display. The "keypad" consists of a incremental wheel with a button-function on the axes an two seperate buttons. So that I can different between right or left turn and 3 different buttons.
• PALCE22V10
  This programmable logicgate generates some additional adresslines for the harddisk and some special controllines for the display.

• PS2-compatible keyboard interface
  In addition I have temporarily connected a PS2-keyboard. But it is not necessary for working as a MP3-player.
• Infrared Receiver
  At the interrupt-input-stage I have provided a IR-diode to read in and decode the signals from a remote control. This function is not implemented yet.
  
• Temperature Sensor
  On the IIC-interface I have reserved a footprint to fit a temperature sensor. This IC is not connected at all.
  
• USB-Interface
  Another prepared IC is the USB-Interface-IC PDIUSBD12 from Philips. This IC is not connected at all.
  

bottom TOP

Schematics and PCB layout

For the prototype I have designed a 2-layer PCB with the dimensions of 10cm x 8cm. So the PCB is 1cm wider than the harddisk. However the PCB includes another circuit for a 16-bit logic-analyzer purpose, which I have cut from the player-pcb - I have not used it until now!.
As you can see, the pcb includes additional IC-footprints (USB) and additional testpins. Until now I have not used these testpins and for the next release they can be removed.

..

top side and bottom side of the PCB.
Click on the pictures to zoom in.

Now, with beginning 2004 I publish a corrected version of the schematics:

The player needs no special power supply. I am using a regulated power plug which delivers 5V at 1000mA.
In the car I am using a common DC/DC-converter. So there is no need to support the wide range of that unregulated voltage in the car.