diff options
| -rw-r--r-- | source/libmaple/api/rcc.rst | 95 |
1 files changed, 48 insertions, 47 deletions
diff --git a/source/libmaple/api/rcc.rst b/source/libmaple/api/rcc.rst index 4bf70d6..ce58ec8 100644 --- a/source/libmaple/api/rcc.rst +++ b/source/libmaple/api/rcc.rst @@ -78,47 +78,6 @@ sources. Switch the SYSCLK source with :ref:`rcc_switch_sysclk() As a special case, you can configure the PLL with a call to :ref:`rcc_configure_pll() <libmaple-rcc-rcc_configure_pll>`. -To set SYSCLK to PLL driven by an external oscillator, you can use -something like this, which is portable except for the initialization -of ``your_pll_cfg``:: - - /* You need to make this point to something valid for your target; see - * the documentation for rcc_configure_pll() for more details. */ - extern rcc_pll_cfg *your_pll_cfg; - - void pll_reconfigure() { - /* Turn on HSI using rcc_turn_on_clk() and wait for it to - * become ready by busy-waiting on rcc_is_clk_ready(). - * - * Switch to HSI to ensure we're not using the PLL while we - * reconfigure it. */ - rcc_turn_on_clk(RCC_CLK_HSI); - while (!rcc_is_clk_ready(RCC_CLK_HSI)) - ; - rcc_switch_sysclk(RCC_CLKSRC_HSI); - - /* Turn off HSE and the PLL, or we can't reconfigure it. */ - rcc_turn_off_clk(RCC_CLK_PLL); - rcc_turn_off_clk(RCC_CLK_HSE); - - /* Reconfigure the PLL. You can also perform any other - * prescaler management here. */ - rcc_configure_pll(your_pll_cfg); - - /* Turn on RCC_CLK_HSE. */ - rcc_turn_on_clk(RCC_CLK_HSE); - while (!rcc_is_clk_ready(RCC_CLK_HSE)) - ; - - /* Turn on RCC_CLK_PLL. */ - rcc_turn_on_clk(RCC_CLK_PLL); - while (!rcc_is_clk_ready(RCC_CLK_PLL)) - ; - - /* Finally, switch to the PLL. */ - rcc_switch_sysclk(RCC_CLKSRC_PLL); - } - .. _libmaple-rcc-rcc_clk: System and Secondary Clock Sources: ``rcc_clk`` @@ -204,8 +163,8 @@ Change the SYSCLK source with ``rcc_switch_sysclk()``. .. _libmaple-rcc-rcc_configure_pll: -Configuring the PLL -~~~~~~~~~~~~~~~~~~~ +PLL Configuration +~~~~~~~~~~~~~~~~~ You can configure the PLL with ``rcc_configure_pll()``. This takes an ``rcc_pll_cfg`` struct as its argument. Though the definition of @@ -213,6 +172,7 @@ You can configure the PLL with ``rcc_configure_pll()``. This takes an target-dependent. .. doxygenstruct:: rcc_pll_cfg +.. _rcc-rcc_configure_pll: .. doxygenfunction:: rcc_configure_pll The fields in an ``rcc_pll_cfg`` on each target are as follows. @@ -247,8 +207,8 @@ The ``data`` field must point to a ``struct stm32f2_rcc_pll_data``. .. _libmaple-rcc-clk-funcs: -System and Secondary Clock Sources -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +System and Secondary Clock Management +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ These functions are useful for managing clocks via their :ref:`rcc_clk <libmaple-rcc-rcc_clk>`. @@ -274,8 +234,8 @@ These functions are useful for managing peripherals via their .. _libmaple-rcc-prescalers: -Prescalers -~~~~~~~~~~ +Prescaler Management +~~~~~~~~~~~~~~~~~~~~ All clock prescalers managed by RCC can be controlled with a single function, ``rcc_set_prescaler()``. @@ -355,5 +315,46 @@ vary by target. Deprecated Functionality ------------------------ +.. _rcc-rcc_clk_init: .. doxygenfunction:: stm32f1::rcc_clk_init +To replace a call to ``rcc_clk_init()`` in order to set SYSCLK to PLL +driven by an external oscillator, you can use something like this, +which is portable except for the initialization of ``your_pll_cfg``:: + + /* You need to make this point to something valid for your target; see + * the documentation for rcc_configure_pll() for more details. */ + extern rcc_pll_cfg *your_pll_cfg; + + void pll_reconfigure() { + /* Turn on HSI using rcc_turn_on_clk() and wait for it to + * become ready by busy-waiting on rcc_is_clk_ready(). + * + * Switch to HSI to ensure we're not using the PLL while we + * reconfigure it. */ + rcc_turn_on_clk(RCC_CLK_HSI); + while (!rcc_is_clk_ready(RCC_CLK_HSI)) + ; + rcc_switch_sysclk(RCC_CLKSRC_HSI); + + /* Turn off HSE and the PLL, or we can't reconfigure it. */ + rcc_turn_off_clk(RCC_CLK_PLL); + rcc_turn_off_clk(RCC_CLK_HSE); + + /* Reconfigure the PLL. You can also perform any other + * prescaler management here. */ + rcc_configure_pll(your_pll_cfg); + + /* Turn on RCC_CLK_HSE. */ + rcc_turn_on_clk(RCC_CLK_HSE); + while (!rcc_is_clk_ready(RCC_CLK_HSE)) + ; + + /* Turn on RCC_CLK_PLL. */ + rcc_turn_on_clk(RCC_CLK_PLL); + while (!rcc_is_clk_ready(RCC_CLK_PLL)) + ; + + /* Finally, switch to the PLL. */ + rcc_switch_sysclk(RCC_CLKSRC_PLL); + } |