Our Emerald-MM PC/104 module gives you 4 serial ports operating at speeds up to 115kbps. In RS-232 mode, the full complement of standard PC serial port signals (8 signals + ground) are provided for each port and are grouped onto two 20-pin headers (2 ports per header). In RS-422 mode, Signals RX+, RX-, TX+, and TX- are provided, along with ground. In RS-485 mode, signals TX+/RX+ and TX-/RX- are provided, along with ground.
5V-only operation and -40 to +85C industrial operating temperature range are standard features. The industry-standard 16C554 UART is compatible with all popular embedded operating systems.
Emerald-MM offers more interrupt level and I/O address options than other quad serial port modules. Therefore, integrating the board into your computer system is a simpler task. Eight different I/O address combinations and 10 different interrupt levels are available.
To help conserve ISA bus interrupts, any number of ports can share the same interrupt level. If you have two boards in one system, both boards can share the same interrupt level as well. An interrupt status register is provided to indicate the status of each serial port's interrupt request signal.
Port Address Selection (Hex)
Interrupt levels are individually selectable for each port. The available interrupt levels are 2, 3, 4, 5, 6, 7, 10, 11, 12, and 15. In addition, a 1K Ohm pulldown resistor is provided for each port.
A single interrupt level can be shared by 2, 3, or 4 ports on one board and can even be shared by more than one board in the system. To enable interrupt sharing, set two or more interrupt level jumpers to the same level and pull out all but one pulldown resistor jumper.