WIP: Add USB HID and framing support over UART

- Add USB HID support.
- Add framing to distinguish between CDC and HID data sent over the UART.
- Add some debug printing.
- Cleanup of code and formatting.

hw/usb_interface/ch552_fw/include/print.h

@@ -0,0 +1,42 @@
+#ifndef __PRINT_H__
+#define __PRINT_H__
+
+#include <stdint.h>
+
+#define DEBUG_PRINT
+//#define DEBUG_SETUP
+//#define UART_OUT_DEBUG
+//#define USE_NUM_U8
+#define USE_NUM_U32
+//#define USE_NEGATIVE_NUMS
+
+void printStr(uint8_t *str);
+void printChar(uint8_t c);
+
+#ifdef DEBUG_SETUP
+#define printStrSetup(x)       printStr(x)
+#define printNumHexSetup(x)    printNumHex(x)
+#else
+#define printStrSetup(x)
+#define printNumHexSetup(x)
+#endif
+
+#ifdef USE_NUM_U8
+int8_t uint8_to_str(uint8_t *buf, uint8_t bufsize, uint8_t n);
+#endif
+
+#ifdef USE_NUM_U32
+int8_t uint32_to_str(uint8_t *buf, uint8_t bufsize, uint32_t n);
+#endif
+
+#ifdef USE_NUM_U8
+void printNumU8(uint8_t num);
+#endif
+
+#ifdef USE_NUM_U32
+void printNumU32(uint32_t num);
+#endif
+
+void printNumHex(uint8_t num);
+
+#endif