The attachment contains a block diagram of the second prototype (Prototype II). This prototype is a new PCB based on the phyCORE tiny module. Essentially, it is our own version of the PhyTec development board provided with the phyCORE tiny development kit.

1. phyCORE Tiny

This is the main interface between the phyCORE tiny module and the rest of the system. The phyCORE tiny module has two 100 pin connectors that make most of the MPC5200B signals available to external logic. I nice block diagram of the phyCORE tiny module can be found in section 1.1 of the phyCORE hardware manual.

2. miniPCI

The phyCORE tiny module makes the PCI signals of the MPC5200 available. We are going to hook these signals up to a miniPCI connector (type IIIA) so we can plug in PC adapter cards. Right now, the only reasonable way to get wireless functionality is via wireless modules (chip manufacturers basically won't talk to us). Most wireless modules come with miniPCI and SPI interfaces. So, we plan on using this interface to try out several wireless cards. At the time of this writing, 802.11n wireless modules with miniPCI connectors are just becoming available. DigiSpeaker might benefit greatly from this new technology and including a miniPCI connector in the design gets us that ability while preserving the flexibility to try other cards.

Not shown in the block diagram is the ability to boot the system from the miniPCI connector. We are thinking that we might route the LocalBus signals to the miniPCI connector (via jumpers) so it is possible to boot the phyCORE tiny card from a flash card of our own creation. The idea here is to make it possible to recover DigiSpeaker from a miniPCI flash card if the system has been 'bricked' by one of our users. phyCORE tiny modules do not route chip select zero to their expansion connector. However, we think it might be possible to scratch off the CS0 line and reroute it to our board (as an experiment with this prototype). Of course, the final DigiSpeaker system will not use the phyCORE tiny module so we will have control over chip select zero.

3. Reset

We plan on providing a push button to reset the system.

4. JTAG

We will probably bring the JTAG signals out to a header so they can be used to test/debug the system. So far, it looks like JTAG equipment is a bit expensive. Our thinking is that the 'boot flash' option discussed in the miniPCI section is a better option.

5. TAS5504/TAS5142

This is the amplifier. It needs a number of connections from the phyCORE tiny card. It needs four GPIO lines for reset, mute, ...etc. It needs I2C for command and control. It needs I2S for signal source. It also needs all three power rails (+30V, +12V & +3.3V) to operate.

The output stage will be laid out so that it is possible to drive two speakers in BTL configuration or four speakers in SE configuration.

6. Power

For this prototype, power will be provided by a lab bench power supply. It will provide +30V and +12V. The power section of this prototype will make +3.3V from the +12V line. Note that the phyCORE tiny module makes +1.5V and +2.5V out of the +3.3V rail.

7. WM8580

This is the input/output section of the prototype. The Wolfson WM8580 provides both analog and digital input and output of signal. It is controlled with I2C and some GPIO lines. Of course, if has to have I2S from the MPC5200 for signal transfer. Notice that the WM8580 is not connected to the TAS5504 directly. All signals (coming or going) pass through the MPC5200.

8. Serial

The phyCORE tiny module provides a UART transceiver on PSC3. This transceiver is used for the serial port of the system. The serial boot is needed for accessing the system during boot.

9. SDCard/MMC

The SPI lines of PSC3 are brought out to an SDcard/MMC connector. They will also be brought out to a header. The thought here is that we can use these signals to control a wireless module or plug in SPI compatible flash cards for more memory. Flash memory on SPI is potentially faster than flash sticks plugged into the USB port.

10. USB

The USB lines of the MPC5200 will be brought out to a USB connector. This was successfully done in the first prototype (see the schematic of the first prototype). The idea here, once again, is to use it for wireless access (there are many cheap wireless USB sticks) or it can be used for flash memory.

11. Ethernet

The phyCORE tiny module provides an Ethernet PHY. This will be reused in the second prototype.

12. InfraRed

The IrDA lines of the MPC5200 have been brought out on the phyCORE connector. We plan on building up a IrDA receiver so remote controls can be used with the system.

13. Insteon

The Insteon prototype kit comes with a board that decodes the control signals into I2C. This prototype will be connected to this prototype so it can be control via Insteon switches and software.