TSensor example in STM32F10x_StdPeriph_Lib_V3.5.0

[zabel]

Posted on September 09, 2011 at 10:41

Hi,

I got the temperature sensor example form the standard library and it works fine on my STM3210E-EVAL board. But I would like to know, why the FSMC must be disabled before a I2C communication is performed. In every iteraten there is the sequence: #ifdef USE_STM3210E_EVAL             /* Disable FSMC */     RCC_AHBPeriphClockCmd(RCC_AHBPeriph_FSMC, DISABLE);     /* Initialize the Temperature Sensor */     LM75_Init(); #endif /* USE_STM3210E_EVAL */            /* Get double of Temperature value */       TempValue = LM75_ReadTemp(); #ifdef USE_STM3210E_EVAL                 /* Enable FSMC */       RCC_AHBPeriphClockCmd(RCC_AHBPeriph_FSMC, ENABLE); #endif /* USE_STM3210E_EVAL */ I tried to comment out the disable/enable calls, and this indeed resulted in not working the example (I get always the same value then), so the disable/enable seems indeed to be needed. But why is this necessary? Regards   Dirk

[Andrew Neil]

Posted on September 09, 2011 at 11:40

The fact that it's conditional on a flag called USE_STM3210E_EVAL suggests that it's something specifically to do with the STM3210E-EVAL board - doesn't it?

So: * Do the STM3210E-EVAL board schematics give any clue? * Is there anything in the STM3210E-EVAL board's User Guide about this?

[zabel]

Posted on September 09, 2011 at 12:03

> The fact that it's conditional on a flag called USE_STM3210E_EVAL suggests that it's

> something specifically to do with the STM3210E-EVAL board - doesn't it? sure. > * Do the STM3210E-EVAL board schematics give any clue? No, the temperature sensor is connected to PB5 (INT), PB6 (SCL) and PB7 (SDA). I don't see how this interferes with the FSMC > * Is there anything in the STM3210E-EVAL board's User Guide about this? Nothing. Regards   Dirk

[Tesla DeLorean]

Posted on September 09, 2011 at 16:20

No, the temperature sensor is connected to PB5 (INT), PB6 (SCL) and PB7 (SDA). I don't see how this interferes with the FSMC

PB7  = I2C1_SDA, FSMC_NADV, TIM4_CH2 (Remap:USART1_TX) Is this sufficiently illuminating?

[zabel]

Posted on September 12, 2011 at 14:38

Thanks, yes. The FSMC_NADV signal is not used on the eval board, but I think it es nevertheless driven as long as the FSMC clock is running.

NB: just found in the errata, that switching off the FSMC clock is a suggested workaround due the to conflict between I2C1 SDA and FSMC_NADV. This leads to another problem I have but this will be a new thread. Regards   Dirk