Your skin naturally produces vitamin D3 when exposed to the sun. Eating fish, beef, and cheese provides a natural boost of vitamin D3, too. Still, vitamin D deficiency is a common problem that can ...

因为要用到2个串口（USART0、USART1），这时候就与要独立的串口打印“usartPrintf”（不能同时重定义到printf）、在配合cjson非常丝滑， ...