/* PLL configuration: PLLCLK = HSI * 6 = 48 MHz */
RCC->CFGR0 &= (uint32_t)((uint32_t)~(RCC_PLLSRC | RCC_PLLXTPRE | RCC_PLLMULL));
#ifdef CH32V30x_D8
RCC->CFGR0 |= (uint32_t)(RCC_PLLSRC_HSI_Div2 | RCC_PLLMULL6);
#else
RCC->CFGR0 |= (uint32_t)(RCC_PLLSRC_HSI_Div2 | RCC_PLLMULL6_EXTEN);
#endif
wch 提供的例子: RCC_PLLSRC_HSI_Div2 RCC_PLLMULL6 为什么不是 HSI/2*6
而是 HSI*6