Usb2.0 Interface Chip Firmware Design And Implementation

Universal Serial Bus (USB) is a new type of serial bus which connects peripherals to computers. Since its advent, USB has rapidly become a standard interface between personal computers (PCs) and peripherals for its high transfer speed and applicability. All PCs on market today support USB interface with no exception, while many peripherals are found with only USB interfaces. It is predictable that USB will be more and more popular with its transfer speed and applicability being increased.Firmware is very important in a USB device project, which affects the transfer speed of USB directly.This dissertation puts forward a new solution on the firmware's design of flash memory disk based on studying USB2.0 protocol, mass storage class and Small Computer System Interface (SCSI) command sets thoroughly. This dissertation describes the key technologies during the realization of firmware being designed.And a complete record of procedures and results through the firmware being debugged are shown, which testifies that the firmware of USB2.0 Interface Controller ASIC achieves the desired sights.In accordance with the Master-Slave architecture in USB 2.0 protocol, the workflow of the firmware is implemented based on interrupt pattern. The firmware program includes three sections: initialization microcontroller and all the peripheral circuits; interrupt service routine, which triggers interrupts and executes the interrupt; task module, which is called by the ISR.During the procedure of realization, main programme implements the initialization of system and waits for the occurrence of interrupt, the ISR calls the task module to execute the operation. The firmware analyzes the protocols and does not disturb the transfer of data. Thus, this procedure can not only guarantee the high transfer speed and good software structure but also simplify the design and test.Due to the strict timing requirements by USB protocol, the firmware must handle certain requests or status within valid periods. Hence during the debugging process, information sent by output program through the serial port can be used to assist debugging and to locate the problems. The debug goes in three steps: Firstly debugging...