A49LF004 Ver la hoja de datos (PDF) - AMIC Technology
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A49LF004 Datasheet PDF : 32 Pages
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A49LF004
Table 2: FWH Read Cycle
Clock
Cycle
Field
FWH[3:0]
MEMORY
I/O
Descriptions
1
START
1101
FWH4 must be active (low) for the part to respond. Only the last
IN
start field (before FWH4 transitioning high) should be
recognized. The START field contents indicate an FWH read
cycle.
Indicates which FWH device should respond. If the IDSEL (ID
2
IDSEL
0000 to 1111
IN
select) field matches the value ID[3:0], then that particular device
will respond to subsequent commands.
3-9
IMADDR
YYYY
These seven clock cycles make up the 28-bit memory address.
IN
YYYY is one nibble of the entire address. Addresses are
transferred most-significant nibble first.
10
IMSIZE
0000 (1 byte)
IN
A field of this size indicates how many bytes will be transferred
during multibyte operations.
IN
In this clock cycle, the master (Intel ICH) has driven the bus to all
11
TAR0
1111
1s and then floats the bus, prior to the next clock cycle. This is
then float the first part of the bus “turnaround cycle.”
12
TAR1
1111 (float)
Float The FWH takes control of the bus during this cycle. During the
then OUT next clock cycle, it will be driven “sync data.”
During this clock cycle, the FWH will generate a “ready-sync”
13
RSYNC 0000 (READY) OUT (RSYNC) indicating that the least-significant nibble of the least-
significant byte will be available during the next clock cycle.
14
DATA
YYYY
OUT YYYY is the least-significant nibble of the data byte.
15
DATA
YYYY
OUT YYYY is the most-significant nibble of the data byte.
OUT In this clock cycle, the A49LF004 has driven the bus to all 1s and
16
TAR0
1111
then floats the bus prior to the next clock cycle. This is the first
then float part of the bus “turnaround cycle.”
17
TAR1
1111 (float)
Float The master (Intel ICH) resumes control of the bus during this
then IN cycle.
FWH Single-Byte Read Waveforms
CLK
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17
FWH4
FWH[3:0]
START IDSEL
IMADDR
IMSIZE TAR0 TAR1 RSYNC
DATA
TAR0 TAR1
PRELIMINARY (November, 2003, Version 0.0)
6
AMIC Technology, Corp.
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