Texas Instruments THUNDERSWITCH II TNETX4090 - Manual (Page 16)

TNETX4090
ThunderSWITCH II

9-PORT 100-/1000-MBIT/S ETHERNET

SWITCH
SPWS044E – DECEMBER 1997 – REVISED AUGUST 1999
16
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
Terminal Functions (Continued)
DIO interface
TERMINAL
I/O
INTERNAL
DESCRIPTION
NAME NO.
I/O
RESISTOR
DESCRIPTION
SAD0
SAD1 AF22
AE22
I Pullup
DIO address bus. Selects the internal host registers provided SDMA is high. Internal pullup
resistors are provided.
SCS AD22 I Pullup
DIO chip select. When low, SCS indicates a DIO port access is valid. An internal pullup resistor
is provided.
SDATA0
SDATA1
SDATA2
SDATA3
SDATA4
SDATA5
SDATA6
SDATA7 AF20
AE20
AD20
AC20
AF21
AE21
AD21
AC21
I/O Pullup DIO data bus. Byte-wide bidirectional DIO port. External pullup resistors are required.
SDMA AF24 I Pullup
DIO DMA select. When low, SDMA modifies the behavior of the DIO interface to allow it to
operate efficiently with an external direct memory access (DMA) controller. SAD0 and SAD1 are
not used to select the internal host register for the access. Instead, the DIO address to access
internal registers is provided by the DMAAddress register, and one of two host register
addresses is selected according to dmainc in SysControl. An internal pullup resistor is provided.
SINT AF19 O None
Interrupt. Interrupt to the attached microprocessor. The interrupt type can be found in the Int
register.
SRDY AF23 O Pullup
DIO ready. When low during reads, SRDY indicates to the host when data is valid to be read.
When low during writes, SRDY indicates when data has been received. SRDY is driven high
for one clock cycle before placing the output in high impedance after SCS is taken high. An
internal pullup resistor is provided.
SRNW AC22 I Pullup
DIO read not write
– When high, read operation is selected.
– When low, write operation is selected.
An internal pullup resistor is provided.
SRXRDY AE23 O None
Network management (NM) port, receive ready. When high, SRXRDY indicates that the NM
port’s receive buffers are completely empty and the NM port is able to receive a frame of any
size up to 1535 bytes in length.
STXRDY AD23 O None
Network management (NM) port, transmit ready. When high, STXRDY indicates that at least
one buffer of frame data is available to be read by the management CPU. It outputs a 1 if any
of the end-of-frame (eof), start-of-frame (sof), or interior-of-frame (iof) bits in NMTxControl is set
to 1, otherwise, it outputs 0.
EEPROM interface
TERMINAL
I/O
INTERNAL
DESCRIPTION
NAME NO.
I/O
RESISTOR
DESCRIPTION
ECLK L26 O None EEPROM data clock. An internal pullup resistor is provided.
EDIO M26 I/O Pullup EEPROM data input/output. An internal pullup resistor is provided.