參數(shù)資料
型號(hào)： AM79C972BKCW
廠商： ADVANCED MICRO DEVICES INC
元件分類： 微控制器/微處理器
英文描述： PCnet⑩-FAST+ Enhanced 10/100 Mbps PCI Ethernet Controller with OnNow Support
中文描述： 5 CHANNEL(S), 100M bps, LOCAL AREA NETWORK CONTROLLER, PQFP16
封裝： PLASTIC, QFP-160
文件頁數(shù)： 30/130頁
文件大小： 1580K
代理商： AM79C972BKCW
30
Am79C972
Expansion ROM Transfers
The host must initialize the Expansion ROM Base Ad-
dress register at offset 30H in the PCI configuration
space with a valid address before enabling the access
to the device. The Am79C972 controller will not react to
any access to the Expansion ROM until both MEMEN
(PCI Command register, bit 1) and ROMEN (PCI Ex-
pansion ROM Base Address register, bit 0) are set to 1.
After the Expansion ROM is enabled, the Am79C972
controller will assert DEVSEL on all memory read ac-
cesses with an address between ROMBASE and
ROMBASE + 1M - 4. The Am79C972 controller aliases
all accesses to the Expansion ROM of the command
types
Memory Read Multiple
and
Memory Read Line
to
the basic Memory Read command. Eight-bit, 16-bit,
and 32-bit read transfers are supported.
Since setting MEMEN also enables memory mapped
access to the I/O resources, attention must be given
the PCI Memory Mapped I/O Base Address register
before enabling access to the Expansion ROM. The
host must set the PCI Memory Mapped I/O Base Ad-
dress register to a value that prevents the Am79C972
controller from claiming any memory cycles not in-
tended for it.
The Am79C972 controller will always read four bytes
for every host Expansion ROM read access. TRDY will
not be asserted until all four bytes are loaded into an in-
ternal scratch register. The cycle TRDY is asserted de-
pends on the programming of the Expansion ROM
interface timing. The following figure (Figure 5) as-
sumes that ROMTMG (BCR18, bits 15-12) is at its de-
fault value.
Note:
The Expansion ROM should be read only during
PCI configuration time for the PCI system.
When the host tries to write to the Expansion ROM, the
Am79C972 controller will claim the cycle by asserting
DEVSEL. TRDY will be asserted one clock cycle later.
The write operation will have no effect. Writes to the Ex-
pansion ROM are done through the BCR30 Expansion
Bus Data Port. See the section on the
Expansion Bus
Interface
for more details. See Figure 5.
Figure 5. Expansion ROM Read
FRAME
CLK
AD
IRDY
TRDY
C/BE
DEVSEL
STOP
PAR
ADDR
CMD
PAR
1
2
3
4
5
48
49
50
51
DATA
PAR
BE
DEVSEL is sampled
21485C-8
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AM79C972BKD/W 制造商:Advanced Micro Devices 功能描述:
AM79C972BKD\\W 制造商:Advanced Micro Devices 功能描述:
AM79C972BKD\W 制造商:Advanced Micro Devices 功能描述:
AM79C972BKIW 制造商:AMD 制造商全稱:Advanced Micro Devices 功能描述:PCnet⑩-FAST+ Enhanced 10/100 Mbps PCI Ethernet Controller with OnNow Support
AM79C972BVC 制造商:Advanced Micro Devices 功能描述:
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