Many typical SPI devices have active low chip selects. An easy thing
to do to use a two-input OR gate in front of each chip select pin. One
input is FSX, the other input comes from a spare DSP output pin. (You
need a spare output for each device on the SPI bus.) Pull that output
pin low to select a device and high to disable it.

David L. Rick
Hach Company
drick@hach.com


hemrin2000@yahoo.com (Jack) wrote in message news:<f313ed98.0309130852.644f2ed6@posting.google.com>...
> I am using the McBSP as a spi master. Can it support only one slave
> device or does it have the capability to support multiple slaves. I
> know that dedicated spi master modules on other processors I have
> worked with have support for more than one device through a few chip
> selects.
> 
> Any help is appreciated,
> Jack

On 13 Sep 2003 09:52:07 -0700, hemrin2000@yahoo.com (Jack) wrote:

>I am using the McBSP as a spi master. Can it support only one slave
>device or does it have the capability to support multiple slaves. I
>know that dedicated spi master modules on other processors I have
>worked with have support for more than one device through a few chip
>selects.
>
>Any help is appreciated,

Device selection (i.e. the chip selects you mention above) needs to be
implemented using some other form of I/O. The McBSP only implements
the serial protocol. 


Best Regards
John McCabe

To reply by email replace 'nospam' with 'assen'

I am using the McBSP as a spi master. Can it support only one slave
device or does it have the capability to support multiple slaves. I
know that dedicated spi master modules on other processors I have
worked with have support for more than one device through a few chip
selects.

Any help is appreciated,
Jack