[BBC-Micro] Harddisc fakery using a microcontroller - back on topic - AVR, FPGA, & SD cards

[Mark Haysman]

----- Original Message ----- 
From: "Phill Harvey-Smith" <afra at aurigae.demon.co.uk>

>> Since single chip micros don't tend to make good bus interfaced
>> peripherals I was wondering if anybody had any experience with
>> AT94K10AL-25AJC.  Its from the Atmel FP Slic family and is a FPGA with
>> an AVR core and can come in a 84 pin PLCC.  I can get them for about
>> AUD30 but they also need their config ram for another $12, and I have to
>> buy 10 of each so its looking a bit pricy to start with.
>>
>> The chip looks very nice for this sort of thing but the licensing for
>> the dev tools is some what draconian. Its free for a very short time,
>> after which I think its about $1200 a year.
>
> Yeah that is the major disadvantage I wish Atmel would get with it and
> release their PLD dev tools for free as Xilinx/Altera etc do, and as
> Atmel themselves do for the AVR etc.

How about a Xilinx Spartan using a Picoblaze processor, or even a Z80 or 
6502 core, there's plenty of space left in an XC3S200A to put a core plus 
other support logic, small ROM and RAM. Yes, you'd need to interface the bus 
to 3.3v, but should be doable with a single LVTH162245, or two at the most 
(I've not looked at how many signals needed). The other side (SD) is already 
3.3v so no problem there.

Mark.