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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262-004US
651
Expansion Bus Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network
Processors
A clock input, EX_CLK, is required to operate the Expansion interface. The maximum
clock frequency supported by the Expansion bus controller is 80 MHz. The clock input is
provided to allow a wide variety of different peripherals to be connected to the
Expansion interface. The GPIO unit provides a clock output after reset and may be
used. Refer to the GPIO chapter for additional details. If a GPIO clock is used, it must
be externally routed on the board to connect to EX_CLK. This implementation gives the
designer the option to choose between a lower part count and the speed of the
interface operations.
To provide a glue-less interface to a wide variety of devices, the Expansion bus
controller supplies eight chips selects to a 32-bit wide external bus, which can be
configured as Intel, Synchronous Intel, Micron ZBT, Motorola, or HPI-style controls. The
signaling characteristics and timing for each chip select is individually programmable.
After chip reset, chip-select 0 defaults to conservative timing values for controlling an
asynchronous flash device and the data width of the flash is determined by the value of
Expansion Bus Address bits 0 and 7 during the reset sequence. The remaining chip
selects are un-programmed. Refer to
“Configuration Register 0” on page 706
additional details.
For Synchronous Intel StrataFlash Memory, the Expansion bus controller only supports
single word asynchronous page-mode read and synchronous burst-mode read (1-8
words). It does not support page mode read mode or single word latched asynchronous
read mode. When configuring a Synchronous Intel StrataFlash Memory, wait polarity
must be programmed to active low, data hold programmed to one clock, wait delay be
deasserted with valid data and clock edge programmed to rising edge. For 16-bit
Synchronous Intel devices, the burst length must be programmed to 16-word bursts.
For 32-bit Synchronous Intel devices, the burst length must be programmed to 8-word
bursts. The latency count must be programmed to the appropriate code that is defined
in the Synchronous Intel StrataFlash Memory specification.
The Expansion Bus interface signals need to be connected based upon the device type
(Intel, Synchronous Intel, Micron ZBT, Motorola, or HPI-style control signals) and a
sample mapping of the pins are shown in
.
Table 217.
Example Expansion Bus Pin Mappings to Target Devices
Pin
Intel
StrataFlash
®
28F128J3D
Synchronous
Intel
StrataFlash
Embedded
Memory (P30)
Motorola*
MCM6946
Micron* ZBT
MT55L128L36F
1
TI* HPI
TMS320UC5409
EX_ALE
OPEN
ADV#
OPEN
ADV/LD#
OPEN
EX_ADDR[24:0]
A[23:0]
A[24:1]
A[18:0]
SA
HCSEL,HCNTL,H
BIL
EX_BE_N[3:0]
OPEN
OPEN
OPEN
BW[d:a]#
OPEN
EX_CS_N[7:0]
CE#
CE#
EN
CE#
hcs
EX_DATA[31:0]
D[15:0]
D[15:0]
DQ[7:0]
DQ
HD[7:0]
EX_IOWAIT_N
OPEN
OPEN
OPEN
OPEN
OPEN
EX_PARITY[3:0]
OPEN
OPEN
OPEN
DQ
OPEN
EX_RD_N
OE#
OE#
G_N
OE#
hr_w_n
EX_RDY_N[3:0]
OPEN
OPEN
OPEN
OPEN
hrdy
EX_WR_N
WE#
WE#
W_N
R/W#
hds1_n
Note:
The # symbol or an _N suffix in a signal name indicates that the signal is asserted low.