USB 2.0 High-Speed 4-Port Hub Controller
Datasheet
20 bytes to send, the first byte would be the number 20 (14h), followed by the 20 bytes of data. The
byte count may not be 0. A Block Read or Write is allowed to transfer a maximum of 32 data bytes.
Note: For the following SMBus tables:
Denotes Master-to-Slave
Denotes Slave-to-Master
Figure 4.1 Block Write
Block Read
A Block Read differs from a block write in that the repeated start condition exists to satisfy the I2C
specification’s requirement for a change in the transfer direction.
Figure 4.2 Block Read
4.4.2
Invalid Protocol Response Behavior
Registers that are accessed with an invalid protocol are not updated. A register is only updated
following a valid protocol. The only valid protocols are Write Block and Read Block, which are
described above.
The Hub only responds to the hardware selected Slave Address.
Attempting to communicate with the Hub over SMBus with an invalid slave address or invalid protocol
results in no response, and the SMBus Slave Interface returns to the idle state.
The only valid registers that are accessible by the SMBus slave address are the registers defined in
the Registers Section. See Section 4.4.3 for the response to undefined registers.
4.4.3
General Call Address Response
The Hub does not respond to a general call address of 0000_000b.
SMSC USB2514
Revision 1.92 (05-08-07)
DATA3S3HEET
SMSC [ SMSC CORPORATION ]
