PCIe-COM-8SM / -4SM User Manual
6
Functional Description
These cards feature high performance 16C950 class UARTs which support the complete
register set of the standard 16C550-type devices. The UARTs support operations in 16C450,
16C550 and 16C950 modes. Each port is capable of data communication speeds up to
3Mbps (standard model up to 460.8kbps in RS-232 mode) in asynchronous mode and has
128-byte deep transmit and receive FIFOs to protect against lost data in multitasking
operating systems, to help reduce CPU utilization and to improve data throughput.
The low profile MD2 form factor allows the card to be installed in small embedded systems.
The card can be used in both a standard profile chassis or in a low profile chassis when used
with the correct mounting bracket. Our PCI Express COM-8SM and -4SM cards ship with a
standard height PCIe mounting bracket installed. This bracket also has threaded inserts
above and below the VHDCI 68-pin connector to facilitate installation of the strengthening
bracket accessory. The industrialized strengthening bracket accessory protects against
damage to the very high density I/O card-mounted connector when side-to-side tension can
occur on the breakout cable.
A crystal oscillator is located on the card. This oscillator permits precise selection of standard
baud rates. Custom baud rates are
available on request, please refer to the “Special Order”
paragraph.
Figure 1-1: Block Diagram
