gd32f150 firmare DAC 的一个小漏洞

只看该作者 · 2015-6-16 15:56

/**
  * @brief  Set the specified data holding register value for DAC channel1.
  * @param  DAC_Align: Specifies the data alignment for DAC channel1.
  * This parameter can be one of the following values:
  *    @arg DAC_ALIGN_8B_R: 8bit right data alignment selected
  *    @arg DAC_ALIGN_12B_L: 12bit left data alignment selected
  *    @arg DAC_ALIGN_12B_R: 12bit right data alignment selected
  * @param  Data: Data to be loaded in the selected data holding register.
  * @retval None
  */
void DAC_SetChannel1Data(uint32_t DAC_Align, uint16_t Data)
{
__IO uint32_t temp = 0;

temp = (uint32_t)DAC_BASE;
temp += DHR12R_OFFSET + DAC_Align;

/* Set the DAC channel1 selected data holding register */
*(__IO uint32_t *) temp = Data;
}

今天正好在调dac,我调用左对齐，数值会把低4位的数据干掉，dac输出的值很小，我仔细看了一下这个函数和相关的寄存器，如果左对齐的话要数据要左移4位，算不算这个函数的一个小漏洞

void DAC_SetChannel1Data(uint32_t DAC_Align, uint16_t Data)
{
__IO uint32_t temp = 0;

temp = (uint32_t)DAC_BASE;
temp += DHR12R_OFFSET + DAC_Align;

if(DAC_Align == DAC_ALIGN_12B_L)
   *(__IO uint32_t *) temp = (Data << 4);
else
   /* Set the DAC channel1 selected data holding register */
   *(__IO uint32_t *) temp = Data;
}