Lpc2000

At 09:33 AM 1/17/05 +0100, you wrote:
>Will this mean that we are not able
>to make simple use of SPI-based serial data flash
>for file storage and SPI based Ethernet MAC/PHY's
>like the one coming up from microchip by simple
>connecting these devices to the SPI bus adding
>additional dedicated select pins from Port 0
>of the LPC210x family.

That's how I read the OP's complaint.  And others have certainly attempted 
to interface serial non volatile memory and this is the first complaint 
I've heard that it would be fundamentally impossible.

As I said I'm about to delve into SPI anyway so I'll investigate this as I 
do and report back.


>I agree I don't know of any device that is just
>8 Bit. SPI is a serial protocol and as such I should
>be able to handle any word-length in a way.

The only micros with HW support that support as low as single bit transfers 
(and I may be misremembering them) are some Motorola (now Freescale) 
devices, the largest I've seen is 32 bits, the Motorola devices I believe 
only went to 8 or 16 depending on the family.  AFAIR even some of them only 
supported (multiples of) 8 bit transfers.  A small number of families 
support variable bit length transfers on an SPI like peripheral but all of 
the ones I've worked with only support 8 bits.  This is widespread enough 
that most of the peripherals I know of that require word lengths that are 
not multiples of 8 (I've seen 12 on occasion) are set up so that you send 
the nearest multiple of 8 and the extra bits are ignored.

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,
be they legal, genetic, or physical.  If you don't believe me, try to
chew a radio signal. "

                         Kelvin Throop, III