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na · 2021-11-09

We get a constant square wave on USART2_TX (PA2) on some of our STM32L451CEU6TR products. This seems to happen sometimes after a power cycle (brown-out). The square wave is a around 32kHz. As mentioned, this only happens on a few of our units, and af...

na · 2016-02-02

Posted on February 02, 2016 at 13:48Hello.How do I know that my design is good enough for all kinds of phones? We have the PCB inside a cabinet, where the phones can max be as close as 3-4cm to the antenna, (a PCB-antenna and a M24LR). How do we ver...

na · 2015-02-17

Posted on February 17, 2015 at 09:49Hello, I can't get either read or write (over I2C) to work correct. If I write the text ''Hello World!!'' from the phone (S3) and then read it over the I2C I get the following error. When I read the length it says...

na · 2021-11-10

static void hsiPllConfig(void){ RCC_OscInitTypeDef RCC_OscInitStruct; RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI; RCC_OscInitStruct.HSIState = RCC_HSI_ON; RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT; ...

na · 2021-11-10

Since we found out that, according to STM32 Application Note, LSCO can be output on PA2, it's safe to assume this is what we see. Question is, how can RCC_BDCR:LSCOEN suddenly be enabled? I don't think we ever touch this register except for setting R...

na · 2021-11-09

I'm using a PSU (tried with several different ones). The unit can be out of power for a long time, and when it starts up it starts to generate this wave again.I'm not sure how this initilize is done (it's not me who have made it), but we suspect that...

na · 2021-11-09

Boot0 is pulled low (by a 10k resistor).

na · 2021-11-09

Sorry, but no. We can't connect a debugger. It's protected, so if we connect a debugger it will erase everything. We have our own debug-output on this UART....

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constant square wave on USART2_TX (PA2) after a power cycle (brown-out)

Verification of antenna/distance

Reading and writing problems (over I2C)

Re: We get a constant square wave on USART2_TX (PA2) on some of our STM32L451CEU6TR products. This seems to happen sometimes after a power cycle (brown-out). The square wave is a around 32kHz.

Re: We get a constant square wave on USART2_TX (PA2) on some of our STM32L451CEU6TR products. This seems to happen sometimes after a power cycle (brown-out). The square wave is a around 32kHz.

Re: We get a constant square wave on USART2_TX (PA2) on some of our STM32L451CEU6TR products. This seems to happen sometimes after a power cycle (brown-out). The square wave is a around 32kHz.

Re: We get a constant square wave on USART2_TX (PA2) on some of our STM32L451CEU6TR products. This seems to happen sometimes after a power cycle (brown-out). The square wave is a around 32kHz.

Re: We get a constant square wave on USART2_TX (PA2) on some of our STM32L451CEU6TR products. This seems to happen sometimes after a power cycle (brown-out). The square wave is a around 32kHz.