Hardware Interface - Intel Embedded Intel486 Hardware Reference Manual

The 82596 coprocessor is an extension of the earlier 82586 LAN coprocessor, which interfaces
an Ethernet network to a 16-bit Intel bus. The 82596 coprocessor can be configured to run soft-
ware drivers written for the 82586 device without modification.
7.6.1.1

Hardware Interface

The 82596 coprocessor communicates with the rest of the system via two hardware interfaces:
the Intel486 processor bus (parallel) interface and the network (serial) interface, as shown in
ure 7-22. The signals for both interfaces are listed in
(including burst cycles), bus interface timing, bus arbitration method, and signal definitions are
compatible with the Intel486 processor. When the coprocessor is not holding the bus, its bus in-
terface signals are floated. The state machines for the Intel486 processor and the 82596 coproces-
sor are very similar.
Network Cable Media
Intel486™
HLDA
Processor
BREQ
Processor Bus
Figure 7-22. 82596CA Application Example
PERIPHERAL SUBSYSTEM
Table 7-12. The coprocessor's bus cycles
Serial
Interface
HOLD
82596
LAN
Controller
Fig-
7-41