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Ivan Ivan
Associate III
August 18, 2017
Question

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

  • August 18, 2017
  • 5 replies
  • 1586 views
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_IN

of 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 STM32F429ZIT6

datasheet. 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):

0690X00000607yRQAQ.png

#stm32f429i-disc1
This topic has been closed for replies.

5 replies

Tesla DeLorean
Guru
August 18, 2017
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.

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Ivan Ivan
Ivan IvanAuthor
Associate III
August 19, 2017
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
Ivan IvanAuthor
Associate III
August 19, 2017
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:

0690X00000607xnQAA.png