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.c

@@ -0,0 +1,188 @@
+#include <stdint.h>
+
+#include "debug.h"
+#include "print.h"
+
+void printStr(uint8_t *str)
+{
+#ifdef DEBUG_PRINT
+    while (*str != 0) {
+        CH554UART0SendByte(*str);
+        ++str;
+    }
+#else
+    (void)str;
+#endif
+}
+
+void printChar(uint8_t c)
+{
+#ifdef DEBUG_PRINT
+    CH554UART0SendByte(c);
+#else
+    (void)c;
+#endif
+}
+
+#ifdef USE_NUM_U8
+int8_t uint8_to_str(uint8_t *buf, uint8_t bufsize, uint8_t n)
+{
+    uint8_t *start;
+
+#ifdef USE_NEGATIVE_NUMS
+    if (n < 0) { // Handle negative numbers.
+        if (!bufsize) {
+            return -1;
+        }
+        *buf++ = '-';
+        bufsize--;
+    }
+#endif
+
+    start = buf; // Remember the start of the string. This will come into play at the end.
+
+    do {
+        // Handle the current digit.
+        uint8_t digit;
+        if (!bufsize) {
+            return -1;
+        }
+        digit = n % 10;
+#ifdef USE_NEGATIVE_NUMS
+        if (digit < 0) {
+            digit *= -1;
+        }
+#endif
+        *buf++ = digit + '0';
+        bufsize--;
+        n /= 10;
+    } while (n);
+
+    // Terminate the string.
+    if (!bufsize) {
+        return -1;
+    }
+    *buf = 0;
+
+    // We wrote the string backwards, i.e. with least significant digits first. Now reverse the string.
+    --buf;
+    while (start < buf) {
+        uint8_t a = *start;
+        *start = *buf;
+        *buf = a;
+        ++start;
+        --buf;
+    }
+
+    return 0;
+}
+#endif
+
+#ifdef USE_NUM_U32
+int8_t uint32_to_str(uint8_t *buf, uint8_t bufsize, uint32_t n)
+{
+    uint8_t *start;
+
+#ifdef USE_NEGATIVE_NUMS
+    if (n < 0) { // Handle negative numbers.
+        if (!bufsize) {
+            return -1;
+        }
+        *buf++ = '-';
+        bufsize--;
+    }
+#endif
+
+    start = buf; // Remember the start of the string. This will come into play at the end.
+
+    do {
+        // Handle the current digit.
+        uint8_t digit;
+        if (!bufsize) {
+            return -1;
+        }
+        digit = n % 10;
+#ifdef USE_NEGATIVE_NUMS
+        if (digit < 0) {
+            digit *= -1;
+        }
+#endif
+        *buf++ = digit + '0';
+        bufsize--;
+        n /= 10;
+    } while (n);
+
+    // Terminate the string.
+    if (!bufsize) {
+        return -1;
+    }
+    *buf = 0;
+
+    // We wrote the string backwards, i.e. with least significant digits first. Now reverse the string.
+    --buf;
+    while (start < buf) {
+        uint8_t a = *start;
+        *start = *buf;
+        *buf = a;
+        ++start;
+        --buf;
+    }
+
+    return 0;
+}
+#endif
+
+#ifdef USE_NUM_U8
+void printNumU8(uint8_t num)
+{
+#ifdef DEBUG_PRINT
+    uint8_t num_str[4] = { 0 };
+    int8_t ret;
+    ret = uint8_to_str(num_str, 4, num);
+    if (!ret) {
+        printStr(num_str);
+    }
+#endif
+}
+#endif
+
+#ifdef USE_NUM_U32
+void printNumU32(uint32_t num)
+{
+#ifdef DEBUG_PRINT
+    uint8_t num_str[11] = { 0 };
+    int8_t ret;
+    ret = uint32_to_str(num_str, 10, num);
+    if (!ret) {
+        printStr(num_str);
+    }
+#else
+    (void)num;
+#endif
+}
+#endif
+
+void printNumHex(uint8_t num)
+{
+#ifdef DEBUG_PRINT
+    // High nibble
+    uint8_t val = num >> 4;
+    if (val <= 9) {
+        val = val + '0';
+    } else {
+        val = (val-10) + 'A';
+    }
+    printChar(val);
+
+    // Low nibble
+    val = num & 0x0F;
+    if (val <= 9) {
+        val = val + '0';
+    } else {
+        val = (val-10) + 'A';
+    }
+    printChar(val);
+#else
+    (void)num;
+#endif
+}