feat: update USART1 baud rate and implement IM1281B communication

Core/Inc/IM1281B.h

@@ -0,0 +1,19 @@
+//
+// Created by Timothy Yin on 2025/3/29.
+//
+#ifndef IM1281B_H
+#define IM1281B_H
+#include "usart.h"
+
+extern uint8_t IM_TxBuf[8];
+extern uint8_t IM_RxBuf[40];
+extern unsigned char IM_ReadFlag, IM_RecvDone, IM_RecvLen;
+extern uint32_t IM_Volt, IM_Curr, IM_Power, IM_Energy, IM_PF, IM_CO2;
+
+unsigned int Calc_CRC(unsigned char crc_buf, unsigned int crc);
+unsigned int Check_CRC(const unsigned char *buf, unsigned char len);
+
+void IM_Read(void);
+void IM_Analyze(void);
+
+#endif //IM1281B_H