IBM EM78M611E manual USB Application, USB Device Controller

EM78M611E

Universal Serial Bus Series Microcontroller

Address
(RD)
0X10	Data Byte Pointer of EP0
0X11	Data Byte Pointer of EP1
0X12	Data Byte Pointer of EP2
		Counter	Pointer	Counter	Pointer	Counter	Pointer
0X00	EP0's FIFO
0X01	EP1's FIFO
0X02	EP1's FIFO
		0		0		0
		1		1		1
		2		2		2
		3		3		3
		4		4		4
		5		5		5
		6		6		6
		7		7		7
		Bi-directional		Uni-directional		Bi-directional

8.5 USB Application

EM78M611E is designed specially for USB device application and has many powerful functions that support the firmware to free itself from complex situation in various aspects of USB application.

8.5.1 USB Device Controller

The EM78M611E built-in USB Device Controller (UDC) can interpret the USB Standard Command and respond automatically without involving firmware. The embedded Series Interface Engine (SIE) handles the serialization and de-serialization of actual USB transmission. Thus, a developer can concentrate his efforts more in perfecting the device actual functions and spend less energy in dealing with USB transaction.

The UDC handles and decodes most Standard USB commands defined in the USB Specification Rev1.1. If the UDC receives an unsupported command, it will set a flag to notify the MCU of the receipt of such command. The Standard Commands that the EM78M611E supports includes; Clear Feature, Get Configuration, Get Interface,

Get Status, Set Address, Set Configuration, Set Feature, and Set Interface.

Each time the UDC receives a USB command, it writes the command into the EP0’s FIFO. Only when it receives unsupported command will the UDC notify the MCU through interrupt.

Hence, the EM78M611E is very flexible under USB application since the developer can freely choose the method of decoding the USB command as dictated by different situation.

22 • Product Specification (V1.1) 11.22.2006

(This specification is subject to change without further notice)