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SMSC USB2502 5.1.2VBus Detect, 5.1.1.18Power-OnTimer, 5.1.1.13Over-CurrentTimer, 5.1.1.15Bus-PoweredMax Power, 5.1.1.14Self-PoweredMax Power

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2-Port USB 2.0 Hub Controller

Datasheet

When Dynamic Power switching is enabled, the Hub detects the availability of a local power source by monitoring the external SELF_PWR pin. If the Hub detects a change in power source availability, the Hub immediately disconnects and removes power from all downstream devices and disconnects the upstream port. The Hub will then re-attach to the upstream port as either a Bus-Powered Hub (if local-power in unavailable) or a Self-Powered Hub (if local power is available).

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.13Over-Current Timer

The time delay (in 2ms increments) for an over-current condition to persist before it is reported to the Host.

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.14Self-Powered Max Power

When in Self-Powered configuration, Sets value in 2mA increments.

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.15Bus-Powered Max Power

When in Bus-Powered configuration, Sets value in 2mA increments.

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.16Self-powered Hub Controller Current

When in Self-Powered configuration, Maximum current requirements of the Hub Controller in 2mA increments.

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.17Bus-Powered Hub Controller Current

When in Bus-Powered configuration, Maximum current requirements of the Hub Controller in 2mA increments.

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.18Power-On Timer

Time (in 2ms intervals) from the time power-on sequence begins on a port until power is good on that port. System software uses this value to determine how long to wait before accessing a powered-on port.

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.19Power Switching Polarity

The selection of active state “polarity” for the PRTPWR2 pin is made by a strapping option only.

5.1.2VBus Detect

According to Section 7.2.1 of the USB 2.0 Specification, a downstream port can never provide power to its D+ or D- pull-up resistors unless the upstream port’s VBUS is in the asserted (powered) state. The VBUS_DET pin on the Hub monitors the state of the upstream VBUS signal and will not pull-up the D+ or D- resistor if VBUS is not active. If VBUS goes from an active to an inactive state (Not Powered), Hub will remove power from the D+ or D- pull-up resistor within 10 seconds.

Revision 2.3 (08-27-07)	18	SMSC USB2502
	DATASHEET

Contents

USB2502 2-PortUSB 2.0 Hub Controller PRODUCT FEATURES ORDER NUMBERS: Table of Contents Chapter List of Tables List of Figures Chapter 1 General Description 1.1OEM Selectable Features Chapter 2 Pin Table 2-Port Page Chapter 3 Pin Configuration 2-PortHub Page Chapter 4 2-PortHub Block Diagram Page Page Page Page Chapter 5 Functional Block Description 5.12-PortHub 5.1.1Hub Configuration Options 5.1.1.5High-SpeedDisable 5.1.1.6EOP Disable 5.1.1.7Current Sensing 5.1.1.8Compound Device 5.1.1.9Non-RemovableDevice 5.1.2VBus Detect 5.2EEPROM Interface 5.2.1I2C EEPROM 5.2.2In-CircuitEEPROM Programming 5.2.3EEPROM DATA 5.2.3.1EEPROM Offset 1:0(h) - Vendor ID 5.2.3.2EEPROM Offset 3:2(h) - Product ID EEPROM Offset 5:4(h) - Device ID 5.2.3.4EEPROM Offset 6(h) - CONFIG_BYTE_1 5.2.3.5EEPROM Offset 7(h) - CONFIG_BYTE_2 5.2.3.6EEPROM Offset 8(h) - Non-RemovableDevice 5.2.3.7EEPROM Offset 9(h) - Port Disable For Self Powered Operation 5.2.3.8EEPROM Offset A(h) - Port Disable For Bus Powered Operation 5.2.3.9EEPROM Offset B(h) - Max Power For Self Powered Operation 5.2.3.10EEPROM Offset C(h) - Max Power For Bus Powered Operation EEPROM Offset D(h) - Hub Controller Max Current For Self Powered Operation 5.3SMBus Slave Interface 5.3.1Bus Protocols 5.3.2Invalid Protocol Response Behavior 5.3.3General Call Address Response 5.3.4Slave Device Time-Out 5.3.5Stretching the SCLK Signal 5.3.6SMBus Timing 5.3.7Bus Reset Sequence 5.3.8SMBus Alert Response Address 5.3.9.1Register 00h: Status/Command (Reset = 0x00) 5.3.9.2Register 01h: Vendor ID (LSB) (Reset = 0x00) Register 02h: Vendor ID (MSB) (Reset = 0x00) Register 03h: Product ID (LSB) (Reset = 0x00) Register 04h: Product ID (MSB) (Reset = 0x00) Register 05h: Device ID (LSB) (Reset = 0x00) Register 06h: Device ID (MSB) (Reset = 0x00) 5.3.9.9Register 08h: Configuration Data Byte 2 (Reset = 0x00) 5.3.9.10Register 09h: Non-RemovableDevice (Reset = 0x00) 5.3.9.11Register 0Ah: Port Disable For Self Powered Operation (Reset = 0x00) 5.3.9.12Register 0Bh: Port Disable For Bus Powered Operation (Reset = 0x00) 5.3.9.13Register 0Ch: Max Power For Self Powered Operation (Reset = 0x00) 5.3.9.14Register 0Dh: Max Power For Bus Powered Operation (Reset = 0x00) 5.3.9.17Register 10h: Power-OnTime (Reset = 0x00) 5.3.9.18Undefined Registers 5.4Default Configuration Option: 5.5Default Strapping Options: 5.6Reset 5.6.1External Hardware RESET_N 5.6.1.2RESET_N for EEPROM Configuration 5.6.1.3RESET_N for SMBus Slave Configuration 5.6.2USB Bus Reset Chapter 6 XNOR Test Chapter 7 DC Parameters 7.1Maximum Guaranteed Ratings 7.2Recommended Operating Conditions Page Page Chapter 8 AC Specifications 8.1Oscillator/Clock 8.1.1SMBus Interface: 8.1.2I2C EEPROM: 8.1.3USB Chapter 9 Package Outlines