XR22801 Datasheet, PDF (15/42 Pages) Exar Corporation – Hi-Speed USB to 10/100 Ethernet Bridge

XR22801
Another feature of the EDGE controller is that up to 2 GPIO pins within the EDGE can be assigned to pulse width modu-
lated (PWM) outputs. Each of the PWM outputs can be used to generate an output clock or pulse of varying duty cycle.
Both low and high cycles can be configured in steps of 267 ns up to 1.092 ms. The output can be controlled to generate a
single "one-shot" pulse or to free run. Refer to the EDGE_PWM0_CTRL and EDGE_PWM1_CTRL registers on page 39
and page 40 for control of PWM outputs.
I²C
The XR22801 implements an I²C multi-master using the control endpoint of the full-speed USB function to transfer data to
and from the I²C interface. The I²C master supports both standard (100 kbps) and fast (400 kbps) modes and supports mul-
tiple master configurations to allow other devices to access slave devices on the I²C. The I²C function is an HID function
and uses the native HID driver. It supports both 7 and 10 bit addressing modes.
Regulated 3.3V Power Output
The XR22801 internal voltage regulator provides 3.3 VDC output power which can be utilized by other circuitry. Refer to
Electrical Characteristics on page 3 for maximum power capability. For bus powered devices, significant utilization of the
3V3 output power may require increasing the maximum power request above the 250 mA default value from the USB host
by programming the OTP.
OTP
The OTP is an on-chip non-volatile memory, that is one-time programmable via the USB interface. Bit locations within the
memory may be programmed at various times allowing for customization of the XR22801. Some bits are pre-programmed
at the factory and caution must be taken not to program any locations except user defined addresses. Contact the factory
[e-mail] for information and assistance in programming the XR22801 OTP.
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