Philips UM10011 5.8.I2C-BusInterface, Philips Semiconductors, ISP1521 Hi-SpeedUSB Hub Demo Board

Philips Semiconductors	UM10011_4
	ISP1521 Hi-Speed USB Hub Demo Board

Figure 5-2: Windows Reporting of the Self-Powered Mode

5.8.I2C-Bus Interface

The ISP1521 can use either its USB descriptors from the internal ROM, or from an external I2C- BusTM EEPROM or microcontroller. Mode selection is done through jumpers J11and J12 (see Table 5-3).

Table 5-3: Mode Selection Using J11 and J12

	J11	J12	Mode	SCL	SDA
	ON	ON	Internal ROM	LOW	LOW
	OFF	OFF	I2C-Bus EEPROM*	HIGH	HIGH
*—Default settings.

An external I2C-Bus controller acting as a master can also be used to update hub descriptors through the CN1 connector.

Note: The I2C-Bus external EEPROM cannot be programmed on-board.

		© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
User manual	Rev. 04.00 — 17 June 2004	10 of 20