hp workstations zx6000, hp server rx2600 - operation and maintenance guide

System Board

System Board Components

Appendix B

185

Dual Serial Controller

The dual serial controller is an EXAR ST16C2550 compatible dual universal

asynchronous receiver and transmitter (DUART). This chip provides enhanced UART

functions with 16-byte FIFOs, a modem control interface and data rates up to 115.2kbps.

There are registers located on this chip that provide onboard error indications and

operation status. There is also an internal loopback capability that allows onboard

diagnostics.

Here are the features provided by this dual serial controller chip:

• Data rates of 115.2kbps with an external clock of 1.8432MHz (fully 16550A

compatible).

• A 16-byte transmit FIFO to reduce the bandwidth requirement of the external CPU

• A 16-byte receive FIFO with error ﬂags to reduce the bandwidth requirement of the

external CPU

• UART control that provides independent transmit and receive

• A Receive FIFO with four selectable interrupt trigger levels

• Modem control signals (-CTS, -RTS, -DSR, -DTR, -RI, -CD, and software controllable

line break)

• Programmable character lengths (5, 6, 7, 8) with Even, Odd or No Parity

• A status report register

Field Programmable Gate Array

The ﬁeld programmable gate array (FPGA) provides ACPI and LPC support for HP’s

Intel® Itanium® 2 platforms based on HP chipsets. This controller is connected to the

PDH bus and provides these features:

• ACPI 2.0 interface

• LPC bus interface to support BMC

• Decoding logic for PDH devices