USB2504A-JT Standard Microsystems (SMSC), USB2504A-JT Datasheet - Page 25

• Manufacturer Part Number: USB2504A-JT
• Manufacturer: Standard Microsystems (SMSC)

Specifications of USB2504A-JT

• Operating Temperature (min): 0C
• Operating Temperature Classification: Commercial
• Operating Temperature (max): 70C
• Package Type: TQFP
• Rad Hardened: No
• Lead Free Status / RoHS Status: Compliant

Integrated USB 2.0 Compatible 4-Port Hub
Datasheet
SMSC USB2504/USB2504A
5.2.3.12
5.2.3.13
5.3
5.3.1
NUMBER
NUMBER
BIT
BIT
7:0
7:0
SMBus Slave Interface
EEPROM Offset E(h) - Hub Controller Max Current For Bus Powered Operation
EEPROM Offset F(h) - Power-On Time
Instead of loading User-Defined Descriptor data from an external EEPROM, the SMSC Hub can be
configured to receive a code load from an external processor via an SMBus interface. The SMBus
interface shares the same pins as the EEPROM interface, if CFG_SEL1 & CFG_SEL0 activates the
SMBus interface, external EEPROM support is no longer available (and the user-defined descriptor
data must be downloaded via the SMBus). Due to system issues, the SMSC Hub waits indefinitely for
the SMBus code load to complete and only “appears” as a newly connected device on USB after the
code load is complete.
The Hub’s SMBus implementation is a subset of the SMBus interface to the host. The device is a
slave-only SMBus device. The implementation in the device is a subset of SMBus since it only supports
two protocols.
The Write Byte and Read Byte protocols are the only valid SMBus protocols for the Hub. The Hub
responds to other protocols as described in
page
The SMBus interface is used to read and write the registers in the device. The register set is shown
in
Bus Protocols
Typical Write Byte and Read Byte protocols are shown below. Register accesses are performed using
7-bit slave addressing, an 8-bit register address field, and an 8-bit data field. The shading indicates
the Hub driving data on the SMBDATA line; otherwise, host data is on the SDA/SMBDATA line.
The slave address is the unique SMBus Interface Address for the Hub that identifies it on SMBus. The
register address field is the internal address of the register to be accessed. The register data field is
the data that the host is attempting to write to the register or the contents of the register that the host
is attempting to read.
Note: Data bytes are transferred MSB first (msb first).
POWER_ON_TIME
Section 5.3.9, "Internal SMBus Memory Register Set," on page
HC_MAX_C_BP
26. Reference the System Management Bus Specification, Rev 1.0.
BIT NAME
BIT NAME
Hub Controller Max Current Bus-Powered: Value in 2mA increments that the
Hub consumes from an upstream port (VBUS) when operating as a self-
powered hub. This value includes the hub silicon along with the combined
power consumption (from VBUS) of all associated circuitry on the board.
This value does NOT include the power consumption of a permanently
attached peripheral if the hub is configured as a compound device.
A value of 50 (decimal) indicates 100mA, which is the default value.
Power On Time: The length of time that is takes (in 2 ms intervals) from the
time the host initiated power-on sequence begins on a port until power is
good on that port.
DATASHEET
25
Section 5.3.2, "Invalid Protocol Response Behavior," on
DESCRIPTION
DESCRIPTION
27.
Revision 2.3 (08-27-07)