ip178a ETC-unknow, ip178a Datasheet - Page 30

• Manufacturer Part Number: ip178a
• Description: 8-port 10/100 Ethernet Integrated Switch
• Manufacturer: ETC-unknow

Initial value set via pins
To set the parameter via pins, connect them to VCC or
ground through resistors. IP178A reads initial value via
configuration pins during the period of reset. An initial
value is set to 1 (0) by connecting a pin to VCC (GND)
through a 10kΩ (1kΩ) resistor as shown on the following
figure. IP178A begins to work after the internal PLL clock
active. To make sure the proper operation of PLL, the
duration of reset must be more than 1 ms. If there is no
setting resistor, IP178A uses the default value.
Preliminary, Specification subject to change without notice
IP178A-DS-P05
Sep. 09, 2002
To set initial value = 1
PAD
RESETB
internal
system
clcok
Power on
< 10us
To set initial value = 0
EEPROM pins are input
PAD
Latch setting on pins
30
EEPROM pins are active
to read EEPROM
EEPROM Interface
During reset, the pins of EEPROM interface are input
signals. At the end of reset, IP178A latches the setting
on configuration pins and begins to read the content in
the EEPROM. The data in EEPROM is valid only if there
is a specific pattern 55AA found in the register 0. If there
is no valid data in EEPROM, IP178A will keep the value
read from resistors setting. After reading the EEPROM,
the pins of EEPROM interface are input signals.
All fields in EEPROM corresponding to the registers of
IP178A should be filled with correct value if an EEPROM
is used. The initial value of IP178A will be replaced with
the content in EEPROM if it is valid. That is, the
EEPROM takes precedence of the pin setting.
IP178A uses a 93C46 EEPROM device. The detail
operation of reading EEPROM is illustrated in the
following figure.
After read EEPROM,
EEPROM pins are input
if MII port is not enabled.
(Advance Version)
IP178A