TNETX3270
ThunderSWITCH 24/3 ETHERNET SWITCH
WITH 24 10-MBIT/S PORTS AND 3 10-/100-MBIT/S PORTS
SPWS043B – NOVEMBER 1997 – REVISED APRIL 1999
11
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Terminal Functions (Continued)
serial MII management PHY interface
TERMINAL
I/O
INTERNAL
DESCRIPTION
NAME NO.
I/O
RESISTOR
DESCRIPTION
MDCLK 121 O/High Z Pullup Serial MII management data clock. MDCLK can be disabled (high impedance) through the
use of the SIO register.
MDIO 120 I/O Pullup Serial MII management data I/O. MDIO can be disabled, placed in high Z, through the SIO
register. An external 4.7-kΩ pullup resistor, conected to VDD(3.3V), is needed to meet the
rise-time requirements.
MRESET 119 O/High Z Pullup Serial MII management reset. MRESET can be disabled (high impedance) through the use
of the SIO register. If connected to a PHY device, an external pullup resistor is
recommended.
EEPROM interface
TERMINAL
I/O
INTERNAL
DESCRIPTION
NAME NO.
I/O
RESISTOR
DESCRIPTION
ECLK 117 O None EEPROM data clock.
EDIO 116 I/O Pullup EEPROM data I/O. An external pulldown resistor may be required for proper operation. Since this
terminal has an internal pullup, it can be left unconnected if no EEPROM is present. The EEPROM
is optional if a management CPU is present.
LED interface
TERMINAL
I/O
INTERNAL
DESCRIPTION
NAME NO.
I/O
RESISTOR
DESCRIPTION
LEDCLK 113 O None LED clock (serial shift clock for the LED status data)
LEDDATA 114 O None LED data (serial LED status data). LEDDATA is active low. All LED information (port link, activity
status, software status, flow status, and fault status) is sent via this serial interface.
JTAG interface
TERMINAL
I/O
INTERNAL
DESCRIPTION
NAME NO.
I/O
RESISTOR
DESCRIPTION
TCLK 106 I Pullup Test clock. TCLK is used to clock state information, test instructions, and test data into and out of the
device during operation of the test port.
TDI 110 I Pullup Test data input. TDI is used to serially shift test data and test instructions into the device during
operation of the test port. An internal pullup resistor is provided on TDI to ensure JTAG compliance.
TDO 108 O None Test data output. TDO is used to serially shift test data and test instructions out of the device during
operation of the test port.
TRST 111 I Pullup Test reset. TRST is used for asynchronous reset of the test-port controller. An internal pullup resistor
is provided to ensure JTAG compliance. If the test port is not used, an external pulldown resistor of
10 kΩ may be used to disable the test-port controller.
TMS 107 I Pullup Test mode select. TMS is used to control the state of the test-port controller. An internal pullup resistor
is provided on TMS to ensure JTAG compliance.