3 cpu timing parameters, 2 endian, Cpu timing parameters – Intel IXF1104 User Manual

Page 122: Endian, Write timing diagram - asynchronous interface, Figure 32

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Intel

®

IXF1104 4-Port Gigabit Ethernet Media Access Controller

Datasheet

122

Document Number: 278757
Revision Number: 009
Revision Date: 27-Oct-2005

5.9.1.3

CPU Timing Parameters

For information on the CPU interface Read and Write cycle AC timing parameters, refer to

Figure

47 “CPU Interface Read Cycle AC Timing” on page 149

,

Figure 48 “CPU Interface Write Cycle

AC Timing” on page 149

, and

Table 54 “CPU Interface Write Cycle AC Signal Parameters” on

page 150

.

5.9.2

Endian

The Endian of the CPU interface may be changed to allow connection of various CPUs to the
Intel

®

IXF1104 4-Port Gigabit Ethernet Media Access Controller. The Endian selection is

determined by setting the Endian bit in the

“CPU Interface ($0x508)"

.

The following describes Endianness control:

There is a byte swapper between the internal 32-bit bus and the external 32-bit bus.

In 8-bit or 16-bit mode operation, the byte packer/byte unpacker holding registers sink and
source data just like the 32-bit external bus in 32-bit mode.

The

“CPU Interface ($0x508)"

selects Big-Endian or Little-Endian mode.

The byte swapper causes the behavior seen in

Table 37

for accessing a register with data bits

data[31:0].

Figure 32. Write Timing Diagram - Asynchronous Interface

T

CAS

T

CAH

T

CWL

T

CDWS

T

CDWD

T

CYD

T

CWH

uPx_Add[12:0]

uPx_WrN

uPx_CsN

uPx_Data[31:0]

uPx_RdyN

T

CDWH

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