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Godson 3A2000 / 3B2000 Processor User Manual
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You can access the configuration header of the corresponding device. The device number is obtained by coding according to PCIMap_Cfg [15: 0] from low to high priority.
The configuration operation address generation is shown in Figure
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Godson 3A2000 / 3B2000 Processor User Manual Part 1
Figure 11-1 Configure read and write bus address generation
The PCI arbiter implements two-level round robin arbitration, bus docking, and isolation of damaged master devices. See its configuration and status
PXArb_Config and PXArb_Status registers. See Table
assignment of PCI bus request and response lines .
Table 11-3 PCI / PCIX bus request and response line assignment
Request and answer line
description
0
Internal integrated PCI / PCIX controller
7: 1
External request 6 ~ 0
The rotation-based arbitration algorithm provides two levels, and the second level as a whole is scheduled as a member of the first level. Dangduo
When a device applies for the bus at the same time, the first level device is rotated once, and the highest priority device in the second level can get
line.
The arbiter is designed to be switched at any time as long as conditions permit. For some PCI devices that do not conform to the protocol
Note that doing so may make it abnormal. Using mandatory priority allows these devices to occupy a
line.
Bus docking refers to whether or not to select one to give an enable signal when no device requests to use the bus. For already
As far as allowed devices are concerned, directly initiating bus operations can improve efficiency. Internal PCI arbiter provides two docking modes
Type: The last master device and the default master device. If you cannot dock in special occasions, you can set the arbiter to
Docking to the default master device 0 (internal controller) and relying on delay 0.
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