STMP15x-SOM Power Up

[pr242]

Hi,

There does not seem to be a Forum Board for this SOM yet, so I will post this here.

Is Olimex sure that the Power Up Sequence is respected?

"When VDD is below 1 V, other power supplies (VDDCORE, VDDA, VDDA1V8_REG,
VDDA1V8_DSI, VDDA1V1_REG, VDD3V3_USBHS/FS, VDDQ_DDR) must remain below
VDD + 300 mV
"

There seems to be a delay on VDD (C104) which would violate the sequence... unless I am missing something.

[LubOlimex]

Well the RC delay was placed there according to document "AN5256
Application note":

https://www.st.com/resource/en/application_note/dm00561921-stm32mp151-stm32mp153-and-stm32mp157-discrete-power-supply-hardware-integration-stmicroelectronics.pdf

Check page 10 and look for the RC group that has arrow with explanation "Recommended RC filter delay for VIN stabilisation".

[pr242]

Thanks for that 

I am intersected in this module but there are some very strange design decisions IMO-
Here are my thoughts:

- Not enough GND pins on the IO connectors. (in my opinion a few more would be a good idea, at *opposite* ends of the connectors, or at least in the middle!)

- No access to IPS. In order to make battery operated equipment, IPS access is useful.

- JTAG. It seems that JTAG is not connected AT ALL. Not even with test points! Is this correct? This is a complete deal breaker for me...

- For industrial applications, on board 100MBit ethernet would be much more useful than audio.

[olimex]

This board is replacement for A13-SOM to offer our existing customer second source for SOC.

So when we designed it we seek 100% compatibility and as A13 have audio but not Ethernet this is the result

Sure this SOM is not optimal for STM32MP1 as it was not designed initially for this SOC

It's good lowest cost entry level SOM.

Hundreds of thousands A13-SOM operate at our customers, this is industrial grade alternative for them.

Definitely bigger SOM optimized for STM32MP1 is to follow, so if you do not like it you will have to wait or make your own.