OX16PCI954_05 Datasheet, PDF (14/73 Pages) Oxford Semiconductor – Integrated Quad UART and PCI interface

OXFORD SEMICONDUCTOR LTD.
OX16PCI954
5 CONFIGURATION & OPERATION
The OX16PCI954 is a multi-function, target-only PCI
device, compliant with the PCI Local Bus Specification,
Revision 2.2 and PCI Power Management Specification,
Revision 1.0.
The OX16PCI954 affords maximum configuration flexibility
by treating the internal UARTs, Local bus and the parallel
port as separate logical functions. Each function has its
own configuration space and is therefore recognised and
configured by the PCI BIOS seperately. The functions
used are configured by the Mode[1:0] pins as shown in
Table 3.
The OX16PCI954 is configured by system start-up
software during the bootstrap process that follows bus
reset. The system scans the bus and reads the vendor and
device identification codes from any devices it finds. It then
loads device-driver software according to this information
and configures the I/O, memory and interrupt resources.
Device drivers can then access the functions at the
assigned addresses in the usual fashion, with the improved
data throughput provided by PCI.
Each function operates as though it was a separate device;
however there are a set of Local configuration registers
that can be used to enable signals and interrupts, configure
timings, and improve the efficiency of multi-port drivers.
This architecture enables separate drivers to be installed
for each function. Generic port drivers can be hooked to
use the functions individually, or more efficient multi-port
drivers can hook both functions, accessing the Local
Configuration Registers from either.
All registers default after reset to suitable values for typical
applications such a 4/8 port serial, or combo 4-port serial/1-
port parallel add-in cards. However, all identification,
control and timing registers can be redefined using an
optional serial EEPROM.
Mode [1:0]
00
01
10
11
Configuration
Function 0 is Quad UART, Function 1 is 8-bit local bus
Function 0 is Quad UART, Function 1 is parallel port
Function 0 is Quad UART, Function 1 is unusable as the local bus pins are used to assign Subsystem
ID and Subsystem Vendor ID to function 0
Function 0 is unusable, Function 1 is 32-bit local bus
Table 3: Mode configuration
DS-0029 Jul 05
External—Free Release
Page 14