diff --git a/cpu/stm32/doc.txt b/cpu/stm32/doc.txt index babfbd6961..cfd065f3e1 100644 --- a/cpu/stm32/doc.txt +++ b/cpu/stm32/doc.txt @@ -1,53 +1,96 @@ /** - * @defgroup cpu_stm32 STM32 - * @ingroup cpu - * @brief All STM32 families code and definitions - * - * This module contains all code and definition to all STM32 cpu - * families supported by RIOT: F0, F1, F2, F3, F4, F7, L0, L4 and WB. - * - * STM32Fx Clock configuration - * =========================== - * - * stm32fx cpus share clock configuration code and macro. - * It can be configured as described here. - * - * The following macro must be defined in the board's periph_conf.h: - * - CLOCK_HSE: 0 if HSI must be used as PLL source, frequency in Hz otherwise, - * - CLOCK_LSE: 0 if LSI must be used as low speed clock, 1 otherwise - * (the LSE is a 32.768kHz crytal) - * - CLOCK_CORECLOCK: desired main clock frequency - * - CLOCK_AHB_DIV, CLOCK_AHB: AHB prescaler in register value and AHB frequecny in Hz - * - CLOCK_APB1_DIV, CLOCK_APB1: APB1 prescaler in register value and APB1 frequecny in Hz - * - CLOCK_APB2_DIV, CLOCK_APB2: APB2 prescaler in register value and APB2 frequecny in Hz - * (CLOCK_APB2_DIV is not needed for stm32f0) - * - * The following macro must be defined for stm32f[2|4|7]: - * - CLOCK_PLL_M, CLOCK_PLL_N, CLOCK_PLL_P, CLOCK_PLL_Q, (CLOCK_PLL_R, optional): - * Main PLL factors - * - * The following macro must be defined for stm32f[0|1|3]: - * - PLL_MUL, PLL_PREDIV: PLL factors. These values are used as is. A PREDIV of 2 - * can be assumed when HSI is selected as PLL input. Some model support any value - * as PREDIV even with HSI though. The `clk_conf` tool will assume PREDIV must be - * to with HSI and will set it accordingly. - * - * The following macro are optional and can be defined depending on board config - * and application needs: - * - CLOCK_ENABLE_PLL_I2S: if a second PLL (PLL I2S) is available on the cpu, it - * can be activated with this macro, then CLOCK_PLL_I2S_M, CLOCK_PLL_I2S_N, - * CLOCK_PLL_I2S_P and CLOCK_PLL_I2S_Q need to be defined, CLOCK_PLL_I2S_R is optional. - * - CLOCK_ENABLE_PLL_SAI: if a second PLL (PLL SAI) is available on the cpu, it - * can be activated with this macro, then CLOCK_PLL_SAI_M, CLOCK_PLL_SAI_N, - * CLOCK_PLL_SAI_P and CLOCK_PLL_SAI_Q need to be defined, CLOCK_PLL_SAI_R is optional. - * - CLOCK_USE_ALT_48MHZ: if the 48MHz clock should be generated by the alternate - * source (PLL I2S or PLL SAI, depending on cpu) - * - * All the previous constants can be generated using the tool in - * `cpu/stm32_common/dist/clk_conf`. - * - * Clock outputs can also be setup with macro: - * - CLOCK_MCOx_SRC, CLOCK_MCOx_PRE, with x=1,2: MCO1 and MCO2 output configuration - * macros. CLOCK_MCOx_SRC defines the MCOx source, as a register value (see vendor header), - * CLOCK_MCOx_PRE defines the MCOx prescaler, as a register value. +@defgroup cpu_stm32 STM32 +@ingroup cpu +@brief All STM32 families code and definitions + +This module contains the code and definitions for STM32 cpu +families supported by RIOT: F0, F1, F2, F3, F4, F7, G0, G4, L0, L1, L4, L5 and WB. + +All constants described below can be configured using `CFLAGS` from the command +line or in the application Makefile. + +Clock configuration +=================== + +All STM32 cpus have clock configuration code and macros. It is recommend to read +the reference manual of the CPU of interest to learn about the corresponding +clock tree and the possible configurations. + +For all families, different input clock sources are available for the SYSCLK +system clock (but only one can be used at a time): + +- HSE (High Speed External): HSE depends on the board configuration and its + presence is specified by the `CONFIG_BOARD_HAS_HSE` constant at board level. + The `CLOCK_HSE` constant specifies the frequency of the external oscillator + in Hz. + To use HSE as system clock (SYSCLK), set `CONFIG_USE_CLOCK_HSE` constant to 1; + +- HSI (High Speed Internal): HSI is either 8MHz or 16MHz, depending + on the families. + To use HSI as system clock (SYSCLK), set `CONFIG_USE_CLOCK_HSI` constant to 1; + +- MSI (Multi-Speed Internal): This internal oscillator is only available on L0, + L1, L4, L5 and WB families. + To use MSI as system clock (SYSCLK), set `CONFIG_USE_CLOCK_MSI` constant to 1 + The MSI clock frequency can be configured using the `CONFIG_CLOCK_MSI` + constant (in Hz); + +- PLL (Phase-Locked Loop) provides a finely configurable clock source for + SYSCLK and allows to reach precise and high clock speeds, depending on the + input source. In RIOT, this is the default clock source for SYSCLK. + To use the PLL as system clock (SYSCLK), set `CONFIG_USE_CLOCK_PLL` constant + to 1 (default). + + If an HSE is provided by the board, it is automatically selected as input + source for the PLL, otherwise HSI is selected. + + On L4 and WB, the PLL input source can be selected between HSE, HSI and MSI + (default): to configure the PLL input source, just set + `CONFIG_CLOCK_PLL_SRC_HSI`, `CONFIG_CLOCK_PLL_SRC_HSE` or + `CONFIG_CLOCK_PLL_SRC_MSI` to 1. + + 2 types of PLL are available on STM32: + - for stm32f[2|4|7], stm32g[0|4] and stm32[l4|l5|wb], the PLL can be + configured with several parameters M, N, P, Q and R (optional). M is the + input divider, N is the multiplier and P, Q and R are output dividers. + On stm32f[2|4|7], the clock source from the P output divider is used as + SYSCLK input, the clock source from the Q output divider can be used as + 48MHz. + On stm32g[0|4] and stm32[l4|l5|wb], the clock source from the R output + divider is used as SYSCLK input. + + Constants used to configure the PLL on these families are + `CONFIG_CLOCK_PLL_M`, `CONFIG_CLOCK_PLL_N`, `CONFIG_CLOCK_PLL_P`, + `CONFIG_CLOCK_PLL_Q` and `CONFIG_CLOCK_PLL_R`. + + - for stm32f[0|1|3] and stm32l[0|1], the PLL can be configured with a + predivider parameter and a multiplier parameter. + Constants used to configure the PLL on these families are + `CONFIG_CLOCK_PLL_DIV` (l0, l1) or `CONFIG_CLOCK_PLL_PREDIV` (f0, f1, f3) + and `CONFIG_CLOCK_PLL_MUL`. + +Advanced Peripheral Bus (APB) clock prescalers: +----------------------------------------------- + +These prescalers are used to compute the PCLK1 and PCLK2 clock values. +Use `CONFIG_CLOCK_APB1_DIV` and `CONFIG_CLOCK_APB2_DIV` constants to configure +the prescalers (just set the frequency factor). +APB2 is not available on f0 and g0 families so setting `CONFIG_CLOCK_APB2_DIV` +will have no effect on them. + +MCO (Microcontroller Clock Output) parameters: +---------------------------------------------- + +For stm32f[2|4|7], clock outputs can be configured as follows: +- set `CONFIG_CLOCK_ENABLE_MCO1` to enable MCO1 (on PA8) and use + `CONFIG_CLOCK_MCO1_PRE` constant to specify the MCO1 prescaler (default to 1). + Possible sources are HSE, HSI and PLL (the default): set 1 to + `CONFIG_CLOCK_MCO1_USE_HSE`, `CONFIG_CLOCK_MCO1_USE_HSI` or + `CONFIG_CLOCK_MCO1_USE_PLL` to select the source; +- set `CONFIG_CLOCK_ENABLE_MCO2` to enable MCO1 (on PC9) and use + `CONFIG_CLOCK_MCO2_PRE` constant to specify the MCO2 prescaler (default to 1). + Possible sources are HSE, SYSCLK, PLLI2S and PLL (the default): set 1 to + `CONFIG_CLOCK_MCO1_USE_HSE`, `CONFIG_CLOCK_MCO1_USE_SYSCLK`, + `CONFIG_CLOCK_MCO1_USE_PLLI2S` or `CONFIG_CLOCK_MCO1_USE_PLL` to select the + source; */