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Dstra.1
Dstra.1
Associate
April 20, 2020
Solved

STM32G071GB (UFQFPN28 - 28 pin package) HSE pins avaliable?

  • April 20, 2020
  • 2 replies
  • 1969 views

i am planning to use HSE on STM32G071GB (UFQFPN28 - 28 pin package)

datasheet STM32G071 on page 41 does really make it clear if HSE pins are available in small package (28pin)

datasheet states:

PC14: OSC32_IN, OSC_IN

PC15: OSC32_OUT

is OSC_OUT missing in datasheet. is there a typo?

This topic has been closed for replies.
Best answer by Tesla DeLorean

A lot of the low pin count devices basically have a CK_IN (HSE BYPASS) where you supply an external​ clock, perhaps a TCXO you already have for a radio, Ethernet or something.

2 replies

Tesla DeLorean
Tesla DeLoreanBest answer
Guru
April 21, 2020

A lot of the low pin count devices basically have a CK_IN (HSE BYPASS) where you supply an external​ clock, perhaps a TCXO you already have for a radio, Ethernet or something.

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Dstra.1
Dstra.1Author
Associate
April 21, 2020

Thank you for your answer.

So, on those low pin count devices, i can't use external high-speed crystal?

(but i could still supply external clock to OSC_IN pin?)

Andreas Bolsch
Andreas Bolsch
Lead III
April 21, 2020

Yes, you could supply an external clock to OSC_IN. Another option would be to use LSE with 32.768 kHz crystal and trim HSI regularly as described in section 5.2.15 in RM. Whether this rather coarse trimming is sufficient depends on your requirements ...

By cascading serveral timers you could even get long term accurancy similar to LSE if you accept some jitter.

Bowman32
Bowman32
ST Employee
April 22, 2020

Hello @Dstra.1​ 

OSC_OUT is not missing in datasheet. Indeed on 32 pins and below, no OSCOUT on G0 devices.

It’s mainly coming from the fact that all embedded peripherals of this device can function properly on the HSI, so no strict constraint on HSE, if for some particular case you need one, no choice then to use an external oscillator system or a TCXO and using OSCIN pin in bypass mode.

Best regards,

Bouraoui

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