Manual Number: 00431-220-5
Page 1-4
SB586T Series Manual
I/O Ports
Two serial ports, J5 and J13, are available, each compatible with the 16550 UART. The serial port at
J13 is extended through a 10-pin header on the board to a bracket-mounted DB-9 connector. Both
serial ports are isolated for protection up to 1500V on signal lines.
Note:
The SB586TU and SB586TT have a 9-pin header at J18 instead of the DB-9 connector.
An enhanced parallel port at J4 is also included, which is capable of bidirectional communication.
The parallel port is extended through a 26-pin header on the board to a bracket-mounted DB-25
connector.
Watchdog Circuit
The watchdog circuit is a hardware timer that resets the CPU if the timer is not refreshed periodi-
cally. The circuit is refreshed by a trigger pulse provided by the onboard MACH 211 programmable
logic device. This timer is enabled by a switch setting on the back of the board, which, when set,
writes a "1" to I/O address 351h, data bit "0". When enabled, software needs to toggle bit "0" at I/O
address 350h once every 650msec to prevent the timer from resetting the CPU. The watchdog
circuit will also reset the CPU if the +5VDC power input falls below 4.75VDC.
Ethernet Connector (SB586TT)
The SB586TT provides a 10/100 BASE-T DEC 21140-AE controller that complies with IEEE 802.3
and ANSI 8802-3 Ethernet standards. The controller features full-duplex operation, onchip DMA to
minimize CPU access, and external/internal loopback capability. An RJ45 connector is provided at
J20 and an Ethernet LED at J21 (to indicate TX and RX links).
Universal Serial Bus (SB586TU)
The SB586TU, with the high-speed, high-capacity Universal Serial Bus (USB), supports ISA/PCI
passive backplanes with up to 16 PCI expansion slots.
Specifications
Unless indicated, the following specifications apply to all models in the SB586T series.
Processors Supported
Intel Pentium, AMD K-6, or AMD K6-2 in a ZIF Socket 7
Processor Clock Rate
100, 133, 166, 200, 233, 266, or 300MHz
ISA Bus Clock Rate
8.33MHz, 24mA line drivers