For a factory new STM32F401CE, does the HSE oscillator run before loading any code?

[John Griessen]

Posted on March 22, 2018 at 04:41

I'm wanting pointers to how to debug a new platform design.  Will the internal oscillator allow loading code via boot0 and the USB port?

Here's the schematic and layout:  

https://github.com/kanzure/culture_shock/blob/master/hardware_schematics_layouts/pyflex_f401.sch.png

 

https://github.com/kanzure/culture_shock/blob/master/hardware_schematics_layouts/pyflex_f401_boost.sch.png

 

https://github.com/kanzure/culture_shock/blob/master/hardware_schematics_layouts/pyflex_f401.assy.png

 

I put a guard ring around the crystals and caps, and kept them short ans symmetric.

When 3.0V applied, I get no oscillations at the HSE output or LSE output measured with an active probe with 3pF loading.

#hardware #stm32f401 #boot #bring-up #crystal

[Tesla DeLorean]

Posted on March 22, 2018 at 04:58

The chip uses the HSI by default. The system loader can use that for USART connectivity. For USB the HSE has to start and benchmark properly.

Should initially try to JTAG onto board and load test code. Check what NRESET and VCAP are doing. 

[John Griessen]

Posted on March 22, 2018 at 07:24

Is JTAG the only way to load with a blank factory STM32F401CE?  I do have a JTAG connector, but have not used one yet.  I have a JTAG STM32F103 board that can run URJTAG, but that is new to me also.  So far, I've started with a running module,

so it could load via USB.

[Tesla DeLorean]

Posted on March 22, 2018 at 08:40

No, but it would give me confidence that things are viable enough to be running from ROM properly.

[John Griessen]

Posted on March 22, 2018 at 08:50

I don't have all the pieces at hand to program a STM32F103 board with dirtyjtag.  I'd need a USB to serial adapter.

I have a nucleoF401.  I might be able to do something with that.  (Looks up howtos on st-link)  Should have had a jtag programmer ready to go now.

[Tesla DeLorean]

Posted on March 22, 2018 at 09:59

The USART mode of the system loader is also a good signs-of-life indicator. Getting code on board allows crystals to fire up, and allow you to feed internal clocks out MCO (PA8) pin.

[John Griessen]

Posted on March 23, 2018 at 05:02

I used an stlink to program a jtag adapter code onto a STM32F103, so now I have 2 tools to observe my new board with. will see tomorrow.