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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Expansion Bus
Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
670
Order Number: 306262-004US
12.4.1.8.5
Synchronous Intel 8-Word Read Access
The above timing diagram shows an 8-word read to a Synchronous Intel device such as
Synchronous Intel StrataFlash. Depending on the EX_CLK period, the latency count bits
in the Intel Synchronous Device read configuration register needs to be programmed
appropriately. The Expansion bus controller will always wait in cycles 1 and 2,
regardless of EX_IOWAIT_N. The device will then assert EX_IOWAIT_N for several
cycles and deassert EX_IOWAIT_N when its ready to transfer data. After the device
deasserts EX_IOWAIT_N, it will transfer the remaining words until all 8 words are
transferred. The Expansion bus controller and Synchronous Intel device both support
wrapping for 8-word reads, therefore ADDR0 is not always aligned to an 8-word
boundary. The STATE signal shows the internal Expansion bus state.
Figure 133. Intel Synchronous 8-Word Read
T
B4400-01
EX_ CLK
- 0 -
- 1 -
- 2 -
- 3 -
- 4 -
- 5 -
- 6 -
- 7 -
- 8 -
- 9 -
EX_CS_N
EX_ ADDR
EX_ ALE
EX_RD_N
EX_WR_N
EX_BE_N
EX_ IOWAIT_N
EX_ DATA
EX_ PARITY
STATE
- 10 -
- 11 -
- 12 -
- 13 -
ADDR0
DATA0
DATA0
PAR0
DATA1
DATA2
ADDRESS
IDLE
DATA3
DATA4
DATA1
DATA2
DATA3
DATA4
DATA5
DATA6
DATA7
PAR1
PAR2
PAR3
PAR4
PAR5
PAR6
DATA5
DATA6
DATA7
PAR7
IDLE
WAIT
WAIT