Need details about STM32 I/Os

[RAMAMOORTH R]

Posted on May 24, 2017 at 18:24

For my design i am already using STM32F429BI--LQFP208 package, Now i am looking to replace this with STM32F777BI-LQFP208, both are pin compatible..

Question: In the data sheet of STM32F777BI Its mentioned that GPIO'S=159 in the page number 17,but in 

STM32F429BI Its mentioned that GPIO'S=168 in page number 16,so what is the difference.

The above one is STM32F777BI,

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

 

The above one is 

STM32F429BI,

http://www.st.com/content/ccc/resource/technical/document/datasheet/03/b4/b2/36/4c/72/49/29/DM00071990.pdf/files/DM00071990.pdf/jcr:content/translations/en.DM00071990.pdf

BUT in the front page of the datasheet -product description its mentioned i/o's 168 in both of the data sheet

and also in the ST.COM  its mentioned i/o's 168 I/O'S

So my question is what is this difference,and what are all  the 9 pins in STM32F777BI  which is not GPIO..

please answer this query....

#stm32f777bi #gpio

[Tesla DeLorean]

Posted on May 24, 2017 at 18:32

Have you worked through the pin list, kind of the first thing I'd do if there was such an anomaly...

[RAMAMOORTH R]

Posted on May 24, 2017 at 21:04

thanks

yes i have gone through all the 208 pins  but there it is mentioned that in STM32F777BI -LQPF208 all the pin type  as i/o for all PINS  except supply and boot and input type pin. Pin Types are same as to the STM32F429BI -LQPF208 only there alternate function varies, but why its mentioned GPIO 159--- i/o's 168.. don't know ------ 

please help regarding this.

[S.Ma]

Posted on May 24, 2017 at 22:06

Compare pinout list in datasheets should give the right answer as Clive said. It should be the reference for comparisons.

[RAMAMOORTH R]

Posted on May 25, 2017 at 00:34

yes totally we have 208 pins in both the ic's  in that  168 i/os is there in both data sheet i have compared all the 168 pins i have attached below 

please find the attachements

https://drive.google.com/open?id=0B_wE-Sq69L5DZGluRmpmOHBmaUk

 

All the 168 pins, there functionality available in the STM32F429BI is available in STM32F777BI, And also in STM32777BI because of upgrade there is some additional  alternate functionality is there i have marked them in yellow color..so please refer this Documents also and tell me

why there is only 159 GPIO'S,  why not 168??, if its 159, what are all the 9 pins that is not GPIO'S. 

[Max]

Posted on May 25, 2017 at 05:01

This seems to be imprecise/generic data in table 2 of STM32F77x datasheet.

The missing GPIOs are taken by the DSI interface on STM32F779 part numbers, so the value is not wrong actually.

The STM32F777 does not have the DSI interface and therefore has all the 168 GPIOs.

You may find the application note useful for your porting task:

http://www.st.com/resource/en/application_note/dm00164538.pdf

Note: I usually use STM32CubeMx to quickly review the pinout, I found this faster than using the datasheet...

[RAMAMOORTH R]

Posted on May 25, 2017 at 07:52

thank you for your information i got it.

[chris cordingley]

Posted on May 25, 2017 at 10:22

Don't worry about it. if the 777 pins do what you want, just do it