The FireMig will be a significant, but not ground-breaking, evolution of the original MiniMig design. It's intended to co-exist with both the (eventual) Clone-A project, as well as the NatAmi projects. Thanks to the newly-released (Q1 2009) MCF52254 microcontroller from Freescale, it will include both USB and Ethernet, and will ship bundled with AROS since distribution of genuine Amiga ROMs and Workbench is Verboten, but will be able to boot from a kickstart image just as the original MiniMig did. The MCF5407 ColdFire CPU contains an integrated SDRAM controller, which allows for 64MBytes of FAST RAM. Nearly all of the V4-ColdFire core MPU designs are borrowed directly from the Freescale M5407C3 Eval Board which, while no longer manufactured (other Eval Boards in the MCF54xx line still are), is a tested design. The 5407 has been chosen for this project as it is the only ColdFire version-4 core based MPU which is not exclusively available in Ball Grid Array (BGA) packaging. The other members of the MCF54xx family are only available in 256, 360, and 388-pin BGA packages. While they are excellent MPUs, and provide significantly more functionality on-die, they've been deemed too time-consuming to work with for the first FireMig iteration.
Bill of Materials
- Xilinx XC3S400-4PQG208C As used in the original Minimig. $25
- Cypress CY7C1049. See Datasheet
- Freescale ColdFire 5407 processor at 162MHz, $29 from Newark , running the free MicroAPL CF68Klib Virtual Machine, instead of using the M68SEC000, ($12-$28 in single quantities)
- In lieu of the original 40MHz PIC18LF252 with integrated 256 x 8 flash, the FireMig uses a 100-LQFP MCF52254AF80 ColdFire V2-core based __microcontroller__, with 512Kbytes embedded flash at 80MHz, which costs $9. Alternatively, the 144-pin MCF52258 can also be used, which costs $10. This provides 96 user I/O pins, versus 56 on the 100-LQFP variant. See http://media.digikey.com/photos/Freescale%20Photos/MCF52254AF80.JPG
- The prototype uses two 4"x4" SchmartBoard|ez proto boards, which allow for very easy hand-soldering of the 208-pin Xilinx FPGA and ColdFire MPU.
- 168-pin SDR DIMM socket, prepopulated with a 64MByte PC66 DIMM.
- 2MBytes of flash, 1MByte of which is user-flashable. The remaining reserved space is used for device initialization and failed-flash recovery.
- U-Boot currently supports the MCF547x ColdFire V4 variant, and is available in the U-Boot Git Source Code Repository