Need quickest path for minimal PCB which includes LQFP144 STM32F407GTx device. Looking for reference design or schematic with BOM. For now I am reading AN4488 Application note. I am using Orcad schematic and layout software. Thanks

[JimH]

The only functionality my board will need to support is digital IO, two RS485 ports and a single RS232 port, but they do not need to be on the first version of the design. We just need to see the board come alive and toggle some IO lines to verify that the code has been properly downloaded.

[JimH]

According to wikipedia: The F4 is pin-to-pin compatible with the STM32 F2-series

From: UM1974 User manual- STM32 Nucleo-144 boards

NUCLEO-F207ZG -> STM32F207ZGT

I can check if these are pin compatible and then reference the Necleo board schematic for the STM32F207ZGT. I will be looking at "AN3364 Application note Migration and compatibility guidelines for

STM32 microcontroller applications" and the STM32F407xx data sheet which again states:

The STM32F405xx and STM32F407xx are part of the STM32F4 family. They are fully pin-to-pin, software and feature compatible with the STM32F2xx devices, allowing the user to

try different memory densities, peripherals, and performances (FPU, higher frequency) for a

greater degree of freedom during the development cycle.

From the datasheet, it looks like the only thing to watch for is pin 143 which needs to be connected to Vdd for STM32F4. So it looks like the schematic for the NUCLEO-F207ZG nucleo will work. Now once I get through all the understanding I will most likely wind up with what TJ is saying.

TJ: I can compare your schematic (minimalist) with the NUCLEO-F207ZG. I think most of the extra busy work in the other schematic is just GPIO which I can throw out to a port. Does it make sense that the NUCLEO-F207ZG will work?

[JimH]

I assume that STM32F407 is more likely to be compatible with STM32F207 rather than say STM32F412ZG since their features are different. It would be nice if there were a single document/web page which has all the compatible mcu's in a single location.

[T J]

You have to get back to what you need,

2x RS485s and 1x RS232.. and LQFP 144...

I totally agree with the use of LQFP parts, so much easier to rework during prototyping..

Basically most STM32 processors will do it.

you have done the code the for RS485 ? that is not trivial.

do you think you will be doing heavy computations ? do you need a FPU ?

any floating point math ? minor or serious time dependent stuff... ?

in the migration Doc you will see there is only some slight changes and 99% of the processors pins are aligned, however the internal peripherals are not always aligned to the same pins.

Choose wisely...

then, since you are developing a product, you should consider the vintage of the processor..

the new STM32L series may be your best step.. I think the newest line is STM32L4R

[John Craven]

There is minimal STM32F407ZxT6 baord here;

https://www.waveshare.com/core407z.htm

wiki here

https://www.waveshare.com/wiki/Core407Z

schematic

https://www.waveshare.com/w/upload/6/6f/CorexxxZ-Schematic.pdf

[T J]

tick, tick, ooops... but a wiring mess to prototype with..

Alternatively,

Its under $100 to get small sample boards(5 pieces) delivered out of China.

Just whip up a PCB, send it off... it will be delivered usually within 10 days.

its not worth your time to play with the toy that has no facilities onboard,

the schematic is what you need, to make you feel comfortable in your processor connection design,

but on your PCB, you want to add the two RS485 drivers/terminators/jumpers and Max232/DB9..., to make your connections robust and trouble free during the development cycle.

then you can work...

it just a few days to do a board... ( plus management delays on client side)