ISP1130
Universal Serial Bus compound hub with integrated keyboard
controller
Rev. 01 鈥?23 March 2000
Objective speci鏗乧ation
1. General description
The ISP1130 integrates a Universal Serial Bus (USB) hub with a keyboard controller
into a single chip, which complies with
Universal Serial Bus Speci鏗乧ation Rev. 1.1
and
the USB
Device Class De鏗乶ition for Human Interface Devices (HID).
The hub has
1 to 2 downstream ports and 1 to 3 non-removable embedded functions, one of
which is dedicated to the keyboard operation. The hub controller is fully implemented
in hardware, ensuring a fast response to host requests.
The integrated 5 V to 3.3 V regulator allows direct connection to the USB power
supply V
BUS
. The downstream ports are either bus-powered or hybrid-powered and
can interface low-power USB devices such as a joystick or a mouse. ISP1130 uses
SoftConnect鈩?technology to connect to the USB host upon detection of V
BUS
. The
low power consumption in 鈥榮uspend鈥?mode allows easy design of equipment that is
compliant with the ACPI鈩? OnNow鈩?and USB power management requirements.
The integrated keyboard controller is based on the 80C51 family and has 8 kbytes of
mask ROM and 256 bytes of data RAM. The code memory is protected against
reading by an external device. A built-in watchdog timer resets the device in case of a
microcontroller hang-up. To reduce power consumption, the microcontroller can be
put in sleep mode or power-down mode.
c
c
A serial I
2
C-bus interface is provided for optional access to an external EEPROM.
This allows the user to program the vendor ID, product ID or activate the built-in
keyboard matrix.
The ISP1130 has built-in overcurrent sense inputs, supporting individual and global
overcurrent protection for downstream ports. All ports (including the hub) have
GoodLink鈩?indicator outputs for easy visual monitoring of USB traf鏗乧. The ISP1130
has a reduced frequency (6 MHz) crystal oscillator to minimize Electro Magnetic
Interference (EMI). These features allow signi鏗乧ant cost savings in system design
and easy implementation of advanced USB functionality into PC peripherals.
2. Features
s
Compound USB hub device with integrated hub repeater, hub controller, Serial
Interface Engine (SIE), data transceivers and 5 V to 3.3 V voltage regulator
s
Complies with
Universal Serial Bus Speci鏗乧ation Rev. 1.1
and
Device Class
De鏗乶ition for Human Interface Devices (HID)
s
Complies with ACPI, OnNow and USB power management requirements