[TriEmbed] Using SPI

Glen Smith mrglenasmith at gmail.com
Tue Apr 1 21:02:58 CDT 2014


My biggest problem with SPI is that shields often use a hard wired pin for
chip select. It always seems like just when I have something figured out, I
discover a pin conflict on a SPI chip select. I guess the good news on this
is that while you can't use the Chip Select pin for anything else, MISO,
MOSI and SCLK can be, with the caveat that you may need to enable / disable
whatever else you attach. (You might not mind LED's flickering while a new
HEX image gets programmed, but having motors spin at the whim of your HEX
image might not be a good idea.)

Glen


On Tue, Apr 1, 2014 at 9:46 PM, Rodney Radford <ncgadgetry at gmail.com> wrote:

> The two data lines MISO and MOSI can be in any state until the falling
> edge of SCLK, so they could conceivably be used for other purposes.
>
> In addition, if the only concern is programming the hex image (which is
> not something you do while the motors are running), you could have some
> jumpers that disconnect the SPI lines from the rest of the circuit while
> downloading the image, and then put them back in place for normal operation.
>
>
>
> On Tue, Apr 1, 2014 at 9:40 PM, Carl Nobile <carl.nobile at gmail.com> wrote:
>
>> Hi all,
>>
>> Is it possible to use the SPI pins on a mircorcontroller for two
>> purposes? For example used to burn the hex image and when not burning the
>> image then in normal running mode used to control motor speed, etc. or
>> something similar. My guess is yes, but I haven't figured out how to do it.
>>
>> Carl
>>
>>
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>>
>>
>
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