am79c970 Advanced Micro Devices, am79c970 Datasheet - Page 28

• Manufacturer Part Number: am79c970
• Description: Pcnettm-pci Single-chip Ethernet Controller For Pci Local Bus
• Manufacturer: Advanced Micro Devices

Disconnect Without Data Transfer
Figure 8 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
PCnet-PCI controller terminates the current transfer
with the deassertion of FRAME on clock 5 and one clock
DEVSEL
FRAME
TRDY
STOP
C/BE
IRDY
REQ
GNT
PAR
CLK
AD
1
DEVSEL is sampled by the PCnet-PCI controller.
ADDRi
0111
2
DATA
PAR
Figure 8. Disconnect Without Data Transfer
3
0000
PAR
4
P R E L I M I N A R Y
Am79C970
5
cycle later with the deassertion of IRDY. It finally re-
leases the bus on clock 6. The PCnet-PCI controller will
re-request the bus after 2 clock cycles to retry the last
transfer. The starting address of the new transfer will be
the same address as of the last untransferred data.
6
7
8
9
10
ADDRi
0111
11
18220C-10
AMD
1-895