This section provides an overview of the Topaz CPU Module and its capabilities. Click on the block diagram for a larger image.

Freescale i.MX25 Applications Processor

The Freescale i.MX25 applications processor is the central component of the Topaz CPU Module. It incorporates an ARM926EJ-S core running at 400MHz along with memory controllers and peripherals which enable connections to a wide range of devices.
The i.MX25 provides many features that are available as part of the Topaz CPU Module. Refer to Chapter 3 for more details on each of these features. 

Packages

The Topaz CPU Module is available in two packages:

1. Surface-mount LGA
2. Plug-in SO-DIMM

LGA Package

This form-factor exposes all interface signals as pads on the bottom surface of the module. Components are only present on the top of the board. It is mounted to a base-board in a similar way to a BGA component.
This form-factor is ideal for high-vibration environments, and products where a small, thin form-factor is essential. It also has a lower overall BOM cost as there is no physical connector.

SO-DIMM Package

This form-factor is the same as that used in lap-top memory modules and other processor modules on the market (although the pin-out is unique to Topaz).
This form-factor provides flexibility during prototyping and early production when compared with the LGA version.

Memory

The Topaz CPU Module includes low-power DDR (LPDDR) and NAND flash memory. Both the RAM and NAND flash operate at 1.8V.
Topaz supports:

• 64MBytes LPDDR.
• 128MBytes+ NAND flash

10/100 Ethernet

The i.MX25 includes a 10/100 Ethernet MAC, and the Topaz Module expands on this functionality by adding a Micrel KSZ8041NL PHY. For detailed information on the MAC, refer to the Freescale documentation.
The signals present on the Topaz interface are:

Power Supply

A Freescale MC93704B Power Management IC is used on the Topaz Module. This provides the power requirements of the chips on the module, as well as power on a main board.
The main rails that can be used are:

• 3.3V internal - 100mA available
• 3.3V external - 500mA available
• 1.8V internal - 100mA available. This is used internally to power the memory ICs. Several signals are 1.8V only due to the power bus assignments on the i.MX25.

Debug

Programming and debugging software on the Topaz CPU Module can be done in a number of ways depending on tools available. These include:

• JTAG. Standard JTAG signals available are TMS, TCK, TDI, TDO and TRST. This requires a JTAG debugger or programmer and the appropriate software.
• USB and serial boot mode.
• Ethernet