20H04 Datasheet, PDF (12/38 Pages) SMSC Corporation – 4-PORT USB2.0 HUB CONTROLLER

Chapter 4 Interface Signal Definition
4-Port USB2.0 Hub Controller
Datasheet
4.1 Pin Descriptions
NAME
RESET_N
SELF_PWR
TEST_P0
TEST_P1
TEST_P2
TEST_P3
ATEST
Table 4.1 - System Interface Signals
BUFFER
TYPE
IS
I
ACTIVE
LEVEL
DESCRIPTION
Low Chip Reset. The minimum active low pulse is 100ns. See section 8.4 for a
complete description of operation following a reset.
High
Self-power Detect. Detects availability of local self-power source:
0: Self/local power source is NOT available (i.e., 4- Port Hub gets all power
from Upstream USB V_BUS).
1: Self/local power source is available.
IPD
N/A Test Pin. Do Not Connect
IPD
N/A Test Pin. Do Not Connect
IPD
N/A Test Pin. Do Not Connect
IPD
N/A Test Pin. Do Not Connect
AO
N/A Test Pin. Do Not Connect
NAME
SMB_SEL_N
CS/EE_SEL
SD/SDA
SCK/SCL
Table 4.2 – Configuration Select and Serial Port Interface
BUFFER
TYPE
I
IO8
IOSD12
IOSD12
ACTIVE
LEVEL
N/A
N/A
N/A
N/A
DESCRIPTION
SMBus Select. Selects between configuration via the SMBus interface, or
from an external EEPROM or using the internal default, as described in
the table below.
SMB_SEL_N CS/EE_SEL
SMBus or EEPROM interface
configuration.
0
0
SMBus slave. Address: 0101100
0
1
SMBus slave. Address: 0101101
1
0
Internal default configuration.
1
1
2-wire EEPROM interface.
Chip Select. This multifunction pin is sampled on the rising edge of
RESET_N. If SMB_SEL_N = 1, the internal default configuration will be
used when this pin is low, or the external I2C EEPROM will supply the
configuration when this pin is high. When SMB_SEL_N = 0, this pin
selects the SMBus slave address, as described in the table above.
Connect a 1k ohm resistor in series with the input when connecting this
pin to either VDD or VSS.
Serial Data. Data I/O on the 2-Wire interface.
Serial Clock. Clock for the 2-Wire interface.
Revision 1.63 (10-14-04)
Page 12
DATASHEET
SMSC USB20H04