global volatile variable changed when calling SPI_I2S_GetFlagStatus - STM32F105

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Jacob Lillie

• January 04, 2011 10:17

Dear All,

 

I am having a problem that I can't seem to solve by myself.

In my main.c file I declare the following as a global variable:

volatile uint8_t Avar;

In the main file I call a function located in another file to read some bytes from an SPI Flash. When this function calls:

SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) then my variable Avar is changed. How can this happen?

To summarise:

The problem basically is that a global variable is changed in the stm lib file: stm32f10x_spi.c as soon as the function SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) is called.

 

Info about my setup.

Release 2.0.7.2010061501.7937

Using STM lib  V3.3.0

Micro: STM32F105RTC6

Compiling in Debug mode with "USE_FULL_ASSERT"

 

Is there something I don't understand about declaring my variables correctly?

Hope someone can help me.

 

Best regards,

 

Jacob Lillie

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  Jon Elliott

  • January 04, 2011 13:25

  Make sure that you've allocated enough stack - see http://rowley.zendesk.com/entries/46160-change-the-stack-size-of-my-application for more information on setting the stack size.

  Best regards,

  Jon Elliott

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  Jacob Lillie

  • January 04, 2011 16:53

  Hi Jon,

  Thanks for the tip. For some reason the settings were not inherited from the main configuration. I changed it from 128 to 1024 bytes and that seem to have done the trick. Thanks again.

  Best regards,

  Jacob

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