Extra Information for SYSTEM CLOCK Driver

Acronyms

Below is a table listing the acronyms used in this module, along with their intended meanings.

Acronym	Description
DFLL	Digital Frequency Locked Loop
MUX	Multiplexer
OSC32K	Internal 32KHz Oscillator
OSC8M	Internal 8MHz Oscillator
PLL	Phase Locked Loop
OSC	Oscillator
XOSC	External Oscillator
XOSC32K	External 32KHz Oscillator
AHB	Advanced High-performance Bus
APB	Advanced Peripheral Bus
DPLL	Digital Phase Locked Loop

Dependencies

This driver has the following dependencies:

• None

Errata

• This driver implements experimental workaround for errata 9905

  "The DFLL clock must be requested before being configured otherwise a write access to a DFLL register can freeze the device." This driver will enable and configure the DFLL before the ONDEMAND bit is set.

Module History

An overview of the module history is presented in the table below, with details on the enhancements and fixes made to the module since its first release. The current version of this corresponds to the newest version in the table.

Changelog
Corrected OSC32K startup time definitions Support locking of OSC32K and XOSC32K config register (default: false) Added DPLL support, functions added: system_clock_source_dpll_get_config_defaults() and system_clock_source_dpll_set_config() Moved gclk channel locking feature out of the config struct functions added: system_gclk_chan_lock(), system_gclk_chan_is_locked() system_gclk_chan_is_enabled() and system_gclk_gen_is_enabled()
Fixed system_gclk_chan_disable() deadlocking if a channel is enabled and configured to a failed/not running clock generator
Changed default value for CONF_CLOCK_DFLL_ON_DEMAND from true to false Fixed system_flash_set_waitstates() failing with an assertion if an odd number of wait states provided
Updated DFLL configuration function to implement workaround for errata 9905 in the DFLL module Updated system_clock_init() to reset interrupt flags before they are used Fixed system_clock_source_get_hz() to return correcy DFLL frequency number
Fixed system_clock_source_is_ready not returning the correct state for SYSTEM_CLOCK_SOURCE_OSC8M Renamed the various system_clock_source_*_get_default_config() functions to system_clock_source_*_get_config_defaults() to match the remainder of ASF Added OSC8M calibration constant loading from the device signature row when the oscillator is initialized Updated default configuration of the XOSC32 to disable Automatic Gain Control due to silicon errata
Initial Release