參數(shù)資料
型號: AM79C972
廠商: Advanced Micro Devices, Inc.
英文描述: PCnet⑩-FAST+ Enhanced 10/100 Mbps PCI Ethernet Controller with OnNow Support
中文描述: PCnet⑩與OnNow增強10/100 Mbps的快速以太網(wǎng)控制器支持的PCI
文件頁數(shù): 38/130頁
文件大?。?/td> 1580K
代理商: AM79C972
38
Am79C972
Figure 16.
Disconnect With Data Transfer
Disconnect Without Data Transfer
Figure 17 shows a target disconnect sequence during
which no data is transferred. STOP is asserted on clock
4 without TRDY being asserted at the same time. The
Am79C972 controller terminates the access with the
deassertion of FRAME on clock 5 and of IRDY one
clock cycle later. It finally releases the bus on clock 7.
The Am79C972 controller will again request the bus
after two clock cycles to retry the last transfer. The
starting address of the new transfer will be the address
of the last non-transferred data.
Target Abort
Figure 18 shows a target abort sequence. The target
asserts DEVSEL for one clock. It then deasserts
DEVSEL and asserts STOP on clock 4. A target can
use the target abort sequence to indicate that it can-
not service the data transfer and that it does not want
the transaction to be retried. Additionally, the
Am79C972 controller cannot make any assumption
about the success of the previous data transfers in the
current transaction. The Am79C972 controller termi-
nates the current transfer with the deassertion of
FRAME on clock 5 and of IRDY one clock cycle later.
It finally releases the bus on clock 6.
Since data integrity is not guaranteed, the Am79C972
controller cannot recover from a target abort event. The
Am79C972 controller will reset all CSR locations to
their STOP_RESET values. The BCR and PCI config-
uration registers will not be cleared. Any on-going net-
work transmission is terminated in an orderly
sequence. If less than 512 bits have been transmitted
onto the network, the transmission will be terminated
immediately, generating a runt packet. If 512 bits or
more have been transmitted, the message will have the
current FCS inverted and appended at the next byte
boundary to guarantee an FCS error is detected at the
receiving station.
FRAME
CLK
AD
IRDY
TRDY
C/BE
DEVSEL
REQ
GNT
PAR
DEVSEL is sampled
ADDRi
0000
0111
PAR
0111
2
3
4
5
6
7
8
9
11
10
PAR
DATA
STOP
ADDRi+8
DATA
1
21485C-19
相關(guān)PDF資料
PDF描述
AM79C972BVIW PCnet⑩-FAST+ Enhanced 10/100 Mbps PCI Ethernet Controller with OnNow Support
AM79C974 PCnetTM-SCSI Combination Ethernet and SCSI Controller for PCI Systems
AM79C974KCW PCnetTM-SCSI Combination Ethernet and SCSI Controller for PCI Systems
AM79C975 PCnet⑩-FAST III Single-Chip 10/100 Mbps PCI Ethernet Controller with Integrated PHY
AM79C973 PCnet⑩-FAST III Single-Chip 10/100 Mbps PCI Ethernet Controller with Integrated PHY
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AM79C972BKC\\W 制造商:Advanced Micro Devices 功能描述:
AM79C972BKC\W 制造商:Advanced Micro Devices 功能描述:
AM79C972BKCW 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
AM79C972BKD/W 制造商:Advanced Micro Devices 功能描述:
AM79C972BKD\\W 制造商:Advanced Micro Devices 功能描述: