Datasheet

High-Speed Inter-Chip (HSIC) USB 2.0 Hub and Flash Media Controller
Datasheet
SMSC USB4640/USB4640i 47 Revision 1.3 (03-13-13)
DATASHEET
4.4.6.1 Protocol Implementation
The hub will only access an EEPROM using the sequential read protocol as outlined in Chapter 8 of
the
MicroChip 24AA02/24LC02B Data Sheet [8].
4.4.6.2 Pull-Up Resistor
The circuit board designer is required to place external pull-up resistors (10 kΩ recommended) on the
SPI_DO/GPIO5/SDA/SPI_SPD_SEL and SPI_CLK/GPIO4/SCL lines (per SMBus 1.0 Specification [7]
and EEPROM manufacturer guidelines) to VDD33 in order to assure proper operation.
4.4.7 In-Circuit EEPROM Programming
The EEPROM can be programmed via automatic test equipment (ATE). Pulling nRESET low tri-states
the device’s EEPROM interface and allows an external source to program the EEPROM.
4.5 Default Configuration Option
The SMSC device can be configured via its internal default configuration. Please see Section 4.3.2 on
page 26 for specific details on how to enable default configuration. Please refer to Table 4.1 for the
internal default values that are loaded when this option is selected.
4.5.1 External Hardware nRESET
A valid hardware reset is defined as assertion of nRESET for a minimum of 1 μs after all power
supplies are within operating range. While reset is asserted, the device (and its associated external
circuitry) consumes less than 500
μA of current.
Assertion of
nRESET (external pin) causes the following:
1. All downstream ports are disabled and
PRTCTL power to downstream devices is removed
2. The PHYs are disabled and the differential pairs will be in a high-impedance state
3. All transactions immediately terminate; no states are saved
4. All internal registers return to the default state (in most cases, 00h)
5. The external crystal oscillator is halted
6. The PLL is halted
4.5.1.1 nRESET for EEPROM Configuration
Figure 4.1 nRESET Timing for EEPROM Mode
t1
t2
t4
t5
t6 t7
nRESET
VSS
Hardware
reset asserted
Device
Recovery/
Stabilization
8051 Sets
Configuration
Registers
Attach USB
Upstream
USB Reset
recovery
Idle
Start completion
request response
t3