STM32F103 - No Internal pull-up on the NRST pin

Posted on February 23, 2017 at 11:48

Hi,

In the current datasheet of STM32F103 (DocID13587 Rev 17) it is written:

5.3.14 NRST pin characteristics

The NRST pin input driver uses CMOS technology.

It is connected to a permanent pull-up resistor, RPU (see Table 35).

In few project we did, we noticed there is no internal pull-up on this pin. (and we needed to add an external pull-up to ensure the mcu work).

Thanks!

#pull-up #stm32f103 #nrst-pin

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Super User

Posted on February 23, 2017 at 12:21

Which part exactly? How do you know the pullup is not there?

JW

Associate III

Posted on February 23, 2017 at 13:22

We used the STM32F103RBT6.

Some students measured floatting values on this NRST pins.

This measure confirm the symptom: these MCU did not launch the program until an external pull-up was added.

Super User

Posted on February 23, 2017 at 20:07

What was the circuitry to which NRST was connected before adding teh pullup?

JW

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