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Coming soon |
1. Introduction
The system clock manager is a feature for system clock managing between multiple users. It determines which frequency is best to suit the system needs. This module also handles the clock management during the low power modes. Good to know: the clock is cut during several low power modes.
2. Concepts
The module is based on a request behavior. Any user – up to 32 - can proceed to a request for clock frequency modification. Among all the requests, the system clock manager determines the one that fulfills the lower possible configuration. The best system clock evaluation is realized at each new request.
On one hand, the decrease clock speed request is handled immediately. On the other hand, the increase clock speed request requires more time to setup. It is not blocking; an interrupt mechanism is used to switch to the requested speed. This permits the firmware to keep running at the actual clock speed until the system is ready. Different clock configurations are possible to request, the supported ones are the following:
- HSE32
- HSE16
- PLL (With a dedicated interface for configuration)
The module also handles the configuration of the Flash and SRAM latencies, the CPU wait states, the configuration of the VOS and the AHB5 divider configuration, depending on the determined clock speed. For the other impacted modules or systems, the user shall adequate and adapt the configurations to the newly set CPU system clock frequency.
3. Interfaces
TBD.
4. How to
TBD.