The word 'alce' mean 'moose' in Portuguese and the usage of this name in the board is related to other previous (huge) stories.
So... the huge wire-maze was starting to freak me out. If for some reason a wire got disconnected I could loose hours searching for the problem. Every time my cat climbed to the desk where I had the breadboards I almost had an heart attack... So I've made a decision: Place everything on a PCB.
Since my goal was to run uClinux and make something useful with it I've decided to design the board with the following specs:
CPU:
- 68HC000P8 (overclocked to 20MHz)
System memory:
- 8Mb SRAM
- 4Mb Flash
Mass storage:
- Micro SD card connector
Peripherals:
- FTDI245 - As an USB serial port
- ENC28J60 - Ethernet controller
- MCP3208 - 8 channel 12bit ADC
- DS12887 - Real time clock + NVRAM
- Lots of GPIO
To control the system I've used the XC9572 CPLD. It's responsible to generate all the control signals for basic system functionality (chip selects, boot address, /rd's & /wr's, ...).
The same XC4010E FPGA from the breadboard is used to control all the peripherals and assist the CPU with whatever signals it needs (almost all CPU pins are available at the FPGA).
Since I didn't want to waist much money with the PCB, I've designed all to fit in a 2 layer PCB, within the minimum area I could use.
And here is a photo of the final PCB produced at Eurocircuits (using their proto PCB service)
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| Alcetronics M68K board (naked PCB) |
From left to right and top to bottom you can see: Flash, SRAM, 68000, FPGA, CPLD, RTC, microSDcard, ftdi245 and ethernet.
In the bottom side there is more FLASH/SRAM, the ADC, 40MHz oscilattor, 5v to 3.3v level converter for the SDcard and the voltage regulators.
And here it is the populated PCB:
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| Alcetronics M68K board |
On the next post I'll talk about the system bring-up, the FPGA contents and current progress in uClinux.
