HardFault accessing variables in ISR

Posted on May 17, 2011 at 13:00

Hi,

I'm playing with an STM32-P103 from Olimex. I started with the ADC DMA example 1, ported it to the target board and removed the SPI functions (not needed for me).

I have a structure;

typedef struct {

u16 dma_buf[ADC_BLEN];

u16 pipe[ADC_PIPE];

u16 head, tail;

u16 status;

u32 int_rms, rms;

} adc_t;

in main.h, and declare a variable

adc_t adc;

in main.c, and as

extern adc_t adc;

in stm32f10x_it.c.

main.c has the needed stuff in the DMA setup I think..

DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_Address;

DMA_InitStructure.DMA_MemoryBaseAddr = (u32) &(adc.dma_buf);

DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;

DMA_InitStructure.DMA_BufferSize = ADC_BLEN;

Now, if I set ADC_BLEN to 512, it runs. If I set to 1024, I get a HardFault.

I removed all references to the variable 'adc' from the DMA ISR, and still the same.

I'm building with CodeSourcery tools, and it compiles and links cleanly with -Wall.

Is there some problem, or limitation, WRT defining the buffer for DMA?

Regards,

James.