The FireMig will be a significant, but not ground-breaking, Mini-ITX-based 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, the FireMig will include both USB host and Ethernet, and will ship bundled with ucLinux, since distribution of genuine Amiga ROMs and Workbench is Verboten; However, it will be able to boot from a kickstart image just as the original MiniMig did. The MCF52254 also includes 512KBytes of integrated flash for booting and program code. 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. Updated versions of the MiniMig's original bootloader, based on the Atmel AT91SAM7S256 ($11) 55MHz ARM7TDMI-based Microcontroller, were evaluated as an option, however since they lack some of the additional features of the aforementioned chips, we opted for the MCF52254 instead, which is more price-competitive.
- Assembled, encased minimigs are selling for just under $300.
- The 667MHz SAM440flex board with no enclosure, RAM, or AmigaOS license, sells for approx $550 USD.
Bill of Materials
- Xilinx XC3S400-4PQG208C As used in the original Minimig. $25
- Cypress CY7C1049 5128x8 SRAM. See Datasheet
- Freescale ColdFire 5407 processor at 162MHz, $29 from Newark , running the free MicroAPL CF68Klib Virtual Machine, in 030 mode, 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.
Boot Loader Options
- U-Boot currently supports the MCF547x ColdFire V4 variant, and is available in the U-Boot Git Source Code Repository
- Colilo a LILO Derivative for ColdFire. Primarily used for loading ucLinux, but there's nothing fundamentally Linux-centric about it.
- dBug is what Freescale gives you. Not really user-friendly, though