DEVICE SPECIFICATION
PCI CONTROLLER
S5933
2.2 ADD-ON INTERFACE
2.3 NON-VOLATILE MEMORY INTERFACE
The S5933 provides a simple, general-purpose inter-
face to the Add-On bus. The Add-On data path is a 32-
bit bus for the S5933. Data transfers to/from the
S5933 internal registers are accomplished through a
chip select decode in conjunction with either a read
or write strobe. The S5933 provides dedicated pins
which allow its FIFOs to be used in the implementa-
tion of custom DMA ports or additional external
FIFOs (if necessary).
The non-volatile interface allows customization of the
S5933 and provides for an optional BIOS ROM on
the PCI bus. The non-volatile memory can be either a
serial device or a byte-wide device. Serial devices
may range from 128 bytes through 2048 bytes, and
byte-wide devices from 128 bytes through 65,536
bytes.
As an example, the Vendor and Device ID numbers
in the PCI configuration space (see Sections 4.1 and
4.2) can be initialized to reflect values contained in
the external non-volatile memory. After initialization,
a user’s own Vendor and Device ID is then presented
by the S5933 when requested by the PCI bus.
The output pins on the Add-On interface include an
interrupt source, a buffered clock, and a software-
controllable reset. The interrupt output pin is provided
to signal when a selected mailbox or self-test event
occurs from the PCI interface. The buffered clock
output is a possible Add-On cost reduction feature,
and in addition provides synchronization for Pass-
Thru data transfers. The software-controllable reset
from the S5933 provides Add-On hardware with a
means for proper handling of a system’s “soft” reboot
(e.g.CTRL-ALT-DEL).
For some non-volatile devices, it is possible to write
the non-volatile memory from the PCI interface. This
feature lets the system designer establish a field up-
grade strategy for the BIOS software or a method to
support various system platforms with only one Add-
On board product.
Use of a byte-wide non-volatile memory device is
shown in Figure 2-6; Figure 2-7 shows a serial device
with the S5933.
Figure 2-6. Byte-Wide Non-Volatile Memory
Interface with S5933
Figure 2-7. Serial Non-Volatile Memory Interface
with S5933
16
EPROM
64KX8
A
EA [15:0]
S5933
1
CS#
OE#
ERD#
EWR#
1
SCL
S5933
Q
R
1
SDA
8
24CO2
24CO4
24CO8
24C16
256X8
512X8
1KX8
2KX8
SERIAL
E2 PROM
EQ[7:0]
Applied Micro Circuits Corporation
6195 Lusk Blvd., San Diego, CA 92121 • (619) 450-9333
2-7
AMCC [ APPLIED MICRO CIRCUITS CORPORATION ]
