On 12/05/2010 06:17 PM, Phill Harvey-Smith wrote:
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 :(
Having used SD on PIC never had to cough up money. The interface is SPI
and the library is not anything special
at last for the SPI interfaced, the 4bit interface I never looked doing
as the project was cheap, not fast.
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.
SD is the slow side.
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.
Yes very likely, or use a PIC24 and take advantage of the pin state
change feature in that flavor.
Allison