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TallGUY
Associate II
August 24, 2018
Solved

STM32F7X internal regulator won't start

  • August 24, 2018
  • 2 replies
  • 1187 views

hello I am using the STM32F779NXH MCU it has an internal 1.2V voltage regulator that I believe should output volt on the CAP_1 and CAP_2 pins. The MCU will not boot, and will not be recognized by the st-link. This is a brand new board and has never been programmed.

I have connected the BYPASS_REG pin directly to GND as stated in the data sheet https://www.st.com/resource/en/datasheet/stm32f777bi.pdf. ( page 33 I believe).

I am wondering if there is anything else I should look for as to why there is no voltage on the CAP_1 and CAP_2 pins.

RESET is held high through a 10K resistor to 3.3V, but the data-sheet doesn't mention that the voltage regulator is dependent on RESET.

Also 3.3V is present and correct.

Attached is an image of the MCU page of the Schematic.

This topic has been closed for replies.
Best answer by waclawek.jan

From that schematic it is not clear whether VDDA is connected to the power supply.

JW

2 replies

waclawek.jan
waclawek.janBest answer
Super User
August 24, 2018

From that schematic it is not clear whether VDDA is connected to the power supply.

JW

TallGUY
TallGUYAuthor
Associate II
August 24, 2018

Good eye, you're a life saver. I owe you all the beers. Blue wired it up and boom it works!​