SMSC USB2524 Chapter 6 Assigning Ports, 6.1Port Assign Interface (PRT_ASSIGN[3:0] pins), 6.1.1Embedded Mode:

USB MultiSwitchTM Hub

Datasheet

Chapter 6 Assigning Ports

There are two different (OEM selectable) methods of assigning downstream ports to upstream hosts. One method is with the PRT_ASSIGN[3:0] interface through the use of mechanical switches or by electrical control of the pins via an external Microcontroller’s GPIO interface. The second method is through the SMBus interface, where the SMBus interface is used to control the switching hub during operation and can switch downstream ports via SMBus commands.

6.1Port Assign Interface (PRT_ASSIGN[3:0] pins)

Assigning ports to either of the upstream host controllers can be accomplished through the 4-wire PRT_ASSIGN interface. The PRT_ASSIGN interface has three operating modes. One is called the Embedded Mode, and the other is Peripheral Mode (with two different electrical “sub” modes; (level triggered or edge triggered).

Note: Any change in PRT_ASSIGN pins will be ignored until the USB2524 is out of reset.

6.1.1Embedded Mode:

The four-pin interface (PRT_ASSIGN[3:0]) operates with only three of the four available pins (PRT_ASSIGN3 is disabled in this mode), which enables a user to select one of 8 pre-determined port assignment configurations. There are 8 “default” configurations, or an OEM can customize the configurations through an EEPROM or SMBus code load.

Note: There is a switching delay determined by the Register D0h: Port Interface Delay Timer.

The configuration is determined by Table 6.1, "USB2524 Port Assign Interface (Embedded Mode)".

Table 6.1 USB2524 Port Assign Interface (Embedded Mode)

							INTERNAL DEFAULT
								CONFIGURATION
	PORT ASSIGN INTERFACE ENCODING					HOST OWNERSHIP OF
						DOWNSTREAM PORTS
PRT_ASSIGN		PRT_ASSIGN	PRT_ASSIGN	PRT_ASSIGN	CONFIG	PORT		PORT	PORT	PORT
3		2	1	0	#	1		2	3	4
X		0	0	0	0	H1		H1	H1	H1
X		0	0	1	1	H2		H2	H2	H2
X		0	1	0	2	H1		H1	H2	H2
X		0	1	1	3	H1		H1	H1	H2
X		1	0	0	4	H2		H2	H2	H1
X		1	0	1	5	H2		H1	H1	H1
X		1	1	0	6	H1		H1	H2	UA
X		1	1	1	7	H1		H1	H1	UA

Note 6.1 H1 = The USB host or hub that is connected to upstream port #1

Note 6.2 H2 = The USB host or hub that is connected to upstream port #2

Note 6.3 UA = Un-Assigned

Revision 1.91 (08-22-07)	18	SMSC USB2524
	DATASHEET