Problems with SPI(ST72254G)

[efeixas]

Posted on March 29, 2004 at 07:50

Problems with SPI(ST72254G)

[efeixas]

Posted on March 26, 2004 at 15:27

We have proved an application with the micro ST72254G connected to one digital potentiometer MCP41010 by SPI. We have followed applications notes of ST and the datasheet of the micro and doing emulation with indart, but it don’t work. Every time we shoot the application it doesn’t receives any answer from SPIF, we have prove it with the oscilloscope and the micro doesn’t produce any signal on ports: SCK or MISO.

Can you give us an example program?

Is it possible that the emulation with indart produces problems with spi communication because it uses the same ports?

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Attachments :

spi.txt : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I0Bf&d=%2Fa%2F0X0000000bUy%2FBu7fY2mVIYXkBrRhri4FZHe1ToY_2gcLDwepNztmS.k&asPdf=false

[sjo]

Posted on March 27, 2004 at 07:38

enric,

I'm afraid you've answered your own question.

On this device the spi pins are also the isp pins and as such cannot be used if you use an indart system.

If you need to debug the spi the cheapest solution is a dvp2 or change to a 264 (the isp pins have been moved on this device).

Example code for the spi is available on this website.

Regards

sjo

[efeixas]

Posted on March 27, 2004 at 10:01

Thank you for the answer.

But I don't know what dvp2 means.

Another question, knowing that I've other unused ports on the micro, could I make spi by software without using the ports used by indart?

[sjo]

Posted on March 28, 2004 at 17:07

DVP2 is the lost cost emulator part: ST7MDT1-DVP2.

Yes do a software spi is another possibility - this is not very hard to do.

Have a look on the apps note pages for examples.

You will be limited by speed though with a software spi.

Regards

sjo

[jatin]

Posted on March 29, 2004 at 07:50

For SPI example code you can refer ST7 Software Library or application note AN970 available on this same site.

You can debug SPI with indart/264 device or 254/DVP2.

[ This message was edited by: Jatin on 29-03-2004 11:21 ]