5 Design Considerations

// ===== Queue Configuration =====
#define USB_TX_BUF_SIZE     8              // Max tasks in USB→I2C queue
#define I2C_TX_BUF_SIZE    8              // Max tasks in I2C→USB queue

// ===== USB/I2C Parameters =====
#define USB_FRAME_PACKAGE   64             // USB Full Speed max packet size (bytes)

Figure 5-1 Buffer Structure

// Represents one 64-byte unit of data (one USB frame)
typedef struct {
    uint8_t buffer[USB_FRAME_PACKAGE];   // Data payload (up to 64 bytes)
    uint16_t length;                     // Actual data length in buffer
} TxElement_t;

// ===== FIFO Queue Structure =====
// Circular queue to manage multiple tasks
typedef struct {
    uint16_t fifoIn;                     // Write pointer (next task to add)
    uint16_t fifoOut;                    // Read pointer (next task to process)
    uint16_t fifoCount;                  // Number of pending tasks in queue
    TxElement_t *fifoPointer;            // Pointer to task array
} TxFIFO_t;