[STM32F429I-DISC1] How to make a board work from external power source?

[Ivan Ivan]

Posted on August 18, 2017 at 16:27

I'm currently developing an app based on STM32F429I-DISC1 board. It works great when the board is connected to STLINK through miniUSB cable, program runs and data are displayed on LCD display. One of the requirements is to make the board work from external power source. I'm using 5V pins to supply power. In this case the program does not start , the screen looks plain white. LD1 COM diode slowly flashes red (It constantly glows red when connected to computer). But when I plug in STLink the program starts. It also keeps running after I remove STLink cable.

Given this, I suppose that the problem is related to Clock setting.

I have looked at Board's Reference manual, on page 18:

OSC clock supply

The following information indicates all configurations for clock supply selection.� MCO from ST-LINK (from MCO of the STM32F429ZIT6)This frequency cannot be changed, it is fixed at 8 MHz and connected to PH0-OSC_INof the STM32F429ZIT6. The configuration needed is:� SB18 closed, SB19 open, R56 removed� SB20, R57, C20, C21, X3 = do not care

This seems to be an initial setting, as shipped from factory (but R56 was in place)

� Oscillator on board (from X3 crystal)

For typical frequencies and its capacitors and resistors, refer to the STM32F429ZIT6datasheet. The configuration needed is:� SB18, SB19, SB20 open� R56, R57, C20, C21, X3 soldered

This seemed likely as an answer to the question, so SB18 has been removed.

It did not help, the board does not start from external power source, but program runs when StLink is plugged (nothing changed).

I have such clock settings (8Mhz at input runs to HSE, PLLCLK is used for SysClock):

#stm32f429i-disc1

[Tesla DeLorean]

Posted on August 18, 2017 at 17:03

Powered the DISCO/NUCLEO with USB Chargers/Batteries here. There was a quirky build of ST-LINK firmware that would hold target in reset, but current firmware doesn't do that.

[Ivan Ivan]

Posted on August 19, 2017 at 07:55

Where can I read about this? There may have been a notice from STM about this.

I got a project in Cube that uses the following package: STM32Cube FW_F4 V1.11.0 . Is it this?

[Ivan Ivan]

Posted on August 19, 2017 at 08:48

I have checked forum somewhat more deep, and found that the common advice here is to use this software. (Not sure what it does...)

https://my.st.com/content/my_st_com/en/products/embedded-software/development-tool-software/stsw-link007.html

 

I don't have any more ideas (removing resistors from board is too risky for me), so here it goes:

[Tesla DeLorean]

Posted on August 19, 2017 at 15:24

Yes, the V2J25 definitely falls into the window of one that misbehaves, the DISC1 was shipped in the thousands of units to Mouser and DigiKey, etc . Stocks might be quite old, and so generally whenever I get DISCO and NUCLEO boards which are not new releases I pull them to current firmware to avoid fighting old demons

The ST-LINK Utilities also ship with an update and drivers, but the stand-alone works well too, some times the releases on the website are not always in sync.

The 5V pin on the header should represent a good 5V_EXT injection point without any mods, based on my scan of the schematic. Like I said I use the Mini USB connector, as wall-wart supplies/chargers, battery packs and car chargers have high availability, and can typically supply 1-2A, which can open doors to higher power peripherals like Cellular modems to run using their own regulators off the 5V rail.

https://community.st.com/message/116455

 

https://community.st.com/message/89288

 

https://community.st.com/message/155109-stm32f429i-disc1-stays-in-reset-mode-when-a-external-powersupply-is-used

 

[Paul Jorgenson]

Posted on October 12, 2017 at 23:51

I was having the same issue and the firmware upgrade fixed the problem with the board.