STM8单片机CAN通信配置问题

只看该作者 · 2019-7-31 11:46

为什么做can通信的函数中都有can_page的读取和最后的写入操作，不可以直接用PSR寄存器控制页面吗？
void CAN_ITConfig(CAN_IT_TypeDef CAN_IT, FunctionalState NewState)
{
uint8_t tmperrorinterrupt = 0;
CAN_Page_TypeDef can_page = CAN_GetSelectedPage();

/* Check the parameters */
assert_param(IS_CAN_IT_CONFIG_OK(CAN_IT));
assert_param(IS_FUNCTIONALSTATE_OK(NewState));

tmperrorinterrupt = (uint8_t)(((uint16_t)CAN_IT) >>7);
tmperrorinterrupt = (uint8_t)((uint8_t)((uint16_t)tmperrorinterrupt & 0xF0) |
                              (uint8_t)((uint8_t)((uint16_t)tmperrorinterrupt & 0x0F) >>1));

CAN->PSR = CAN_Page_Config;
if (NewState != DISABLE)
{
      /* Enable the selected CAN interrupt */
      CAN->IER |= (uint8_t)(CAN_IT);
      CAN->Page.Config.EIER |= (uint8_t)(tmperrorinterrupt);
}
else
{
      /* Disable the selected CAN interrupt */
      CAN->IER &= (uint8_t)~(uint8_t)((uint16_t)CAN_IT);
      CAN->Page.Config.EIER &= (uint8_t)~(tmperrorinterrupt);
}
/*Restore Last Page*/
CAN_SelectPage(can_page);
}