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How to recognize which STM32F7xx microcontroller has DSI and which doesn't?

Pawel Piwowarski
Associate II
Posted on May 08, 2017 at 12:56

Hi.

So, main page says:

0690X00000603mmQAA.jpg

So it suggest that STM32F7x8 and 7x9 has DSI, and lowest (7x2 to 7x7) doesn't.

Unfortunately if we enter a specific type of microcontroller, exampleSTM32F777BI, we see general information about all family, not information about this specific microcontroller:

0690X00000603ppQAA.jpg

So we will not see if the DSI is or not.

Maybe compare table?

0690X00000603pVQAQ.jpg0690X00000603FJQAY.jpg

These two should not have a DSI.

But i have STM32F769BI microcontrollers and PCB for it (my own design, for microcontrollers without DSI). And after soldering something make me a short curcuit on the VCC line (uC takes a lot of current and get hot). I measured another uC pins with the multimeter (before soldering to PCB) and it looks like it corresponds to a pinut of DSI controller.

All table clearly states that it should not have DSI (uC with DSI on red, my uC (without DSI as I expect), on green):

0690X00000603paQAA.jpg

The difference between uC with and without is DSI is mainly on 125pin (pin 125), because it is VDD12DSI or VSS depending on presence of DSI.

So the microcontroller VDD12DSI pin, gets on the VSS pad on my PCB. And make a short circuit.

125 pin in my STM32F769BI (outside the PCB) do not have connection to other VSS pins. So i guess that is not a VSS pin, and it is VDD12DSI pin.

And pins 122 and 128 are not floating. So i guess they are not PJ10 and PK2, but they ale both VSSDSI.

Finally, how to choose a microcontroller without DSI (to fit my PCBs), since you cannot rely on the table and the description?

Thanks.

3 REPLIES 3
Khouloud GARSI
Lead II
Posted on May 08, 2017 at 18:20

Hi

Piwowarski.Pawel

‌,

So it suggest that STM32F7x8 and 7x9 has DSI, and lowest (7x2 to 7x7) doesn't.

-> Correct;

Unfortunately if we enter a specific type of microcontroller, exampleSTM32F777BI, we see general information about all family, not information about this specific microcontroller:

-> Please refer to table2 in the

http://www.st.com/content/ccc/resource/technical/document/datasheet/group3/8a/34/ed/7e/4c/04/4b/7a/DM00225424/files/DM002254pdf/jcr:content/translations/en.DM002254pdf

related to STM32F777BI device. This table will give you the exact information about which devices do have the DSI and which don't.

  • In your case, for the

    STM32F769BI device, theDSI host interface is available.

This could be checked using table2 in the related

http://www.st.com/content/ccc/resource/technical/document/datasheet/group3/c5/37/9c/1d/a6/09/4e/1a/DM00273119/files/DM00273pdf/jcr:content/translations/en.DM00273pdf

.

0690X00000606xhQAA.png

Also, there is anote under the table indicating that for the devices listed in this datasheet:

4. DSI host interface is only available on STM32F769x sales types.

Section2.4 ''DSI Host availability across STM32 microcontrollers'' can also answer your question.

  • I hope that this is more clear. For further details, do not hesitate to post your questions in our STM32 forum.

Khouloud.

Pawel Piwowarski
Associate II
Posted on May 08, 2017 at 21:27

Thanks.

I've already seen AN4860. But there is no answer to my question, because in the section:

Availability of DSI Host among STM32 microcontrollers

it is only the main information about all microcontrollers from F7xx family.

And I'm a little afraid to rely on the datasheet, since the information in it does not correspond the parameters in the table.

Because in that case it is not known who tells the truth. A table or datasheet?

Couldn't these data match to each other?

Posted on May 12, 2017 at 20:24

Hi

Piwowarski.Pawel

‌,

  • Please refer to the datasheet. It's always our first reference.
  • In AN4860, the section ''DSI Host availability across STM32 microcontrollers'' indicates clearlythat, for the STM32F7 devices, the DSI Host peripheral is only available on STM32F7x8 and STM32F7x9 lines.

0690X00000606zxQAA.png

If youselectthe ''STM32F7'' family and choose the ''DSIHOST'' in section ''peripheral choice'', you will have a list of all the STM32 devices with DSI Host support:The STM32F769BI is one of those devices.

0690X00000606utQAA.png

  • Regarding the table, I will report the issue and this will be corrected as soon as possible. I will keep you posted about any further update.

Thanks a lot for bringing this to our attention and sorry for any inconvenience this may have caused.

Khouloud.