Specification
NET2272 USB Peripheral Controller
______________________________________________________________________________
NetChip Technology, Inc., 2003
Patent Pending
335 Pioneer Way, Mountain View, California 94041
TEL (650) 526-1490
FAX (650) 526-1494
http://www.netchip.com
Rev 1.2, October 15, 2003
17
2.3
Clocks, Reset, Misc. (8 pins)
Signal Name
Pin
Type
Description
XIN
25
I
Oscillator input. Connect to 30 MHz crystal or external oscillator
module.
XOUT
26
O
Oscillator output. Connect to crystal, or leave open if using an external
oscillator module. The oscillator stops when the device is suspended.
LCLKO
57
O,
12mA,
TS
Local Clock Output. This pin is a buffered clock output from the internal
PLL, with the frequency depending on the state of the Local Clock Output
field in the LOCCTL configuration register. This pin stops oscillating as
soon as the NET2272 is put into suspend mode, and is not driven while the
device is suspended.
When the internal oscillator is started, LCLKO is
prevented from being driven for 2 msec. LCLKO doesn’t oscillate while
the chip is in the power-down mode.
RESET#
58
I, S
Reset. External reset. Connect to local or power-on reset. To reset when
oscillator is stopped (initial power-up or in suspend state), assert for at
least two milliseconds. When oscillator is running, assert for at least five
60 MHz clock periods.
VBUS
64
I, S
USB VBUS. This input indicates when the NET2272 is connected to a
powered-up USB host connector.
An external 47K pull-down resistor
should be connected to this pin to keep it low when not connected to the
USB.
TEST
18
I
Test input. Connect to ground for normal operation.
TRST
40
I
TRST Test input. TAP controller reset. Connect to ground for normal
operation.
TMC2
17
I
TMC2 Test input. I/O buffer control. Connect to ground for normal
operation.
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