Bit-banding on STM32L series

[infoinfo988]

Posted on June 03, 2011 at 11:50

Hi,

I'm trying to get bit-banding to work on STM32L series. It seems that some header  definitions have changed between STM32F and STM32L so it's not clear how bit-banding should be implemented.

I've tried the following:

&sharpdefine BITBAND_PERI_REF   0x40000000

&sharpdefine BITBAND_PERI_BASE  0x42000000

&sharpdefine BITBAND_PERI(a,b) ((BITBAND_PERI_BASE + (a-BITBAND_PERI_REF)*32 + (b*4)))  // Convert PERI address

//Offset of ODR in GPIO_TypeDef = 0x14?

//GPIOA ODR = 0x40000000 + 0x00020000 + 0x000 + 0x14

//GPIOB ODR = 0x40000000 + 0x00020000 + 0x400 + 0x14

//GPIOC ODR = 0x40000000 + 0x00020000 + 0x800 + 0x14

//GPIOD ODR = 0x40000000 + 0x00020000 + 0xC00 + 0x14

&sharpdefine GPIOA_BB(b) *((volatile uint32_t *)(BITBAND_PERI(0x40020014,b)))

&sharpdefine GPIOB_BB(b) *((volatile uint32_t *)(BITBAND_PERI(0x40020414,b)))

&sharpdefine GPIOC_BB(b) *((volatile uint32_t *)(BITBAND_PERI(0x40020814,b)))

&sharpdefine GPIOD_BB(b) *((volatile uint32_t *)(BITBAND_PERI(0x40020C14,b)))

But it doesn't seem to work. Any ideas on how we can solve this?

Thanks.

#bit-banding-stm32l

[Tesla DeLorean]

Posted on June 03, 2011 at 15:15

The following seems to be viable on the STM32L platform, with a Keil compiler.

Not sure what you're using, but you could verify the actual addresses of the pointers you are using to confirm they match the correct values.

{ // STM32L152-EVAL Test

    volatile unsigned long *odr_a            = (volatile unsigned long *)0x40020014;

    volatile unsigned long *odr_a_bb    = (volatile unsigned long *)0x42400280;

    sprintf(text,''%08X %08X'',*odr_a,GPIOA->ODR);

  GLCD_DisplayString(0, 0, (unsigned char *)text);

    odr_a_bb[0] = 1;

    odr_a_bb[4] = 1;

    sprintf(text,''%08X %08X'',*odr_a,GPIOA->ODR);

  GLCD_DisplayString(1, 0, (unsigned char *)text);

    odr_a_bb[0] = 0;

    odr_a_bb[8] = 1;

    sprintf(text,''%08X %08X'',*odr_a,GPIOA->ODR);

  GLCD_DisplayString(2, 0, (unsigned char *)text);

}

The output is

00000000 00000000

00000011 00000011

00000110 00000110