AMD Geode CS5535, Руководство по портированию

Страница: 27 / 36

AMD Geode™ GX Processor/CS5535 Companion Device GeodeROM Porting Guide 27
5
Implementation 32430C
5.0
Implementation
5.1 Implementation
The following is a collection of implementation details to consider in the GeodeROM implementation phase.
5.1.1 Clocking
There are two clock inputs to the GX processor: the system PCI clock (SYSREF) used to derive the Core clock, and the
GeodeLink™ clock used for the memory clock. The Dot clock is used for video display control. The Core and GeodeLink
clocks can be programmed and restarted by reseting the GX processor.
5.1.2 Scratchpad Initialization
The scratchpad is no longer needed either for BLT buffers or by the audio code for variable storage. The scratchpad is not
supported in the GX processor CPU Core.
5.1.3 Post Codes
Post codes are sent out to port 80 throughout GeodeROM. A Post codes list is available in the AMD Geode™ GeodeROM
Functional Specification (publication ID 32087) to help users debug their problems.