SPI speed limitation

[Stijn Goris]

hi all,

Does SPI serial communication have a speed limitation? I guess so bu I can't
seem to find information regarding it's speed...

regards
Stijn

 

[Rene Tschaggelar]

Stijn Goris wrote:

hi all,

Does SPI serial communication have a speed limitation? I guess so bu I can't
seem to find information regarding it's speed...

Each device specifies a max clock.
Lookup the datasheets.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

 

[Spehro Pefhany]

On Thu, 06 May 2004 11:42:21 GMT, the renowned "Stijn Goris"
<mepisto@hotmail.com> wrote:

hi all,

Does SPI serial communication have a speed limitation? I guess so bu I can't
seem to find information regarding it's speed...

You have to look in detail at the timing diagrams of the devices on
the bus and make sure that all are operating within specifications for
both read and write (if the latter mode is used). That's after you get
the mode right.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Stijn Goris]

"Rene Tschaggelar" <none@none.net> wrote in message
news:409a2c3b$0$720$5402220f@news.sunrise.ch...

Stijn Goris wrote:
hi all,

Does SPI serial communication have a speed limitation? I guess so bu I
can't
seem to find information regarding it's speed...

Each device specifies a max clock.
Lookup the datasheets.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

I m designing a product for my schoolproject. I want to communicate between
a processor and a SPI bus. I don't have a specific component in mind but i m
just wondering if 10Mbit/s communication would be possible with SPI?

regards

 

[Spehro Pefhany]

On Thu, 06 May 2004 12:45:48 GMT, the renowned "Stijn Goris"
<mepisto@hotmail.com> wrote:

"Rene Tschaggelar" <none@none.net> wrote in message
news:409a2c3b$0$720$5402220f@news.sunrise.ch...
Stijn Goris wrote:
hi all,

Does SPI serial communication have a speed limitation? I guess so bu I
can't
seem to find information regarding it's speed...

Each device specifies a max clock.
Lookup the datasheets.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

I m designing a product for my schoolproject. I want to communicate between
a processor and a SPI bus. I don't have a specific component in mind but i m
just wondering if 10Mbit/s communication would be possible with SPI?

regards

So long as you don't have specific components in mind, sure, just
about anything is possible.

When you get to real parts, for example, some Atmel EEPROMs are spec'd
to operate at 10MHz (provided the other timing requirements are met),
but only at 5V Vdd. At lower Vdd you might be restricted to half that
or less.

If you want to communicate with as many different devices as possible,
I'd suggest 2MHz at 5V Vdd as a good compromise between speed and
versatility. That's only 4usec to simultaneously send/receive one
byte, which isn't too bad. You'll eat up a bit more diddling the /CS
so you get diminishing returns on the SPI clock rate for a fixed
processor cycle time.

One exception where you might want to push toward the maximum is
dragging large amounts of data out of SEEPROMs in
auto-address-increment mode, where you leave the chip selected for a
relatively large number of cycles (you just set up the mode and
address, and keep clocking it, and data keeps coming out like a big
shift-register until you stop or something glitches). You can also
dynamically change the clock rate in many cases to allow for chips
that are slower than others.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com