USB97C202 ETC, USB97C202 Datasheet - Page 9

• Manufacturer Part Number: USB97C202
• Description: ATA/ATAPI CONTROLLER
• Manufacturer: ETC

USB 2.0 ATA/ATAPI Controller
Datasheet
SMSC USB97C202
USB Bus
Data
USB
Transceiver
Filter
USB
Transceiver
Bias
Termination
Resistor
Full Speed
USB Data
Memory Data
Bus
Memory
Address Bus
Memory Write
Strobe
Memory Read
Strobe
IO Read
Strobe
IO Write
Strobe
Crystal
Input/External
Clock Input
Crystal Output XTAL2
Clock Output CLKOUT
Internal ROM
Enable
USB-
USB+
LOOPFLTR
RBIAS
RTERM
FS-
FS+
MD[7:0]
MA[15:0]
nMWR
nMRD
nIOR
nIOW
XTAL1/
CLKIN
ROMEN
DATASHEET
MEMORY/IO INTERFACE
IO12PU When ROMEN=0, these signals are used to
OCLKx
ICLKx
IO-U
IO-U
O12
O12
O12
O12
O12
O8
IP
USB INTERFACE
MISC
Page 9
These pins connect to the USB bus data
signals.
This pin provides the ability to supplement the
internal filtering of the transceiver with an
external network, if required.
A 9.09 Kohm precision resistor is attached
from ground to this pin to set the transceiver’s
internal bias currents.
A precision 1.5Kohm precision resistor is
attached to this pin from a 3.3V supply.
These pins connect to the USB- and USB+
pins through 31.6 ohm series resistors.
transfer data between the internal CPU and the
external program memory. When ROMEN=1, a
weak internal pull up is activated to prevent
these pins from floating.
These signals address memory locations within
the external memory.
Program Memory Write; active low
Program Memory Read; active low
XDATA space Read; active low
XDATA space Write; active low
12Mhz Crystal or external clock input.
This pin can be connected to one terminal of
the crystal or can be connected to an external
12Mhz clock when a crystal is not used.
12Mhz Crystal
This is the other terminal of the crystal, or left
open when an external clock source is used to
drive XTAL1/CLKIN. It may not be used to
drive any external circuitry other than the
crystal circuit.
This pin produces a 30Mhz clock signal
independent of the processor clock divider. It is
held inactive and low whenever the internal
processor clock is stopped or is being obtained
from the ring oscillator.
When left unconnected or tied high, the
USB97C202 uses the internal ROM for
program execution. When tied low, an external
program memory should be connected to the
memory/data bus. The state of this pin latched
internally on the rising edge of nRESET.
Revision 1.2 (02-04-04)