Phill Harvey-Smith afra at
Sun Dec 5 17:17:57 CST 2010

On 05/12/2010 22:51, maurice smulders wrote:
> Atmel  and ST have ARM chips which have an SD port (4bits) - and i
> suspect there might be others...

Do you have part numbers ?

> Another option are the PIC24 chips. They have a 8/16 bit master slave
> port which could be used for the SCSI interface... I think a device
> could be made pretty small with a 28 pin MCU and a microSD socket...
> Most likely a bit faster than an AVR solution... And small..

With propper 4 bit SD no doubt, talking to it by SPI is always gonna be 
slower, but do those chips actually have the SD protocl built in, IIRC 
that was one of those you have to sign an NDA and pay $$$/£££ to get 
hold of :(

I don't think it's the SCSI interface that is slowing the thing down 
TBH, I rather suspect that the SPI-SD is the culpret.

You'd also probably need some interface logic between the slave port on 
a PIC, between it and the SCSI data lines. Also the AVR I have used has 
a usefull feature where you can tag a bunch of pins and generate an 
interrupt when any of them changes, this is how I monitor the reset, 
SEL, ACK and ATN pins.

I have a version now designed with IDE and SCSI, time to start building 
it up on breadboard....



Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.

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