diff options
| -rw-r--r-- | libmaple/include/libmaple/i2c.h | 17 | ||||
| -rw-r--r-- | libmaple/stm32f1/include/series/i2c.h | 10 |
2 files changed, 26 insertions, 1 deletions
diff --git a/libmaple/include/libmaple/i2c.h b/libmaple/include/libmaple/i2c.h index d327c72..6d1fadf 100644 --- a/libmaple/include/libmaple/i2c.h +++ b/libmaple/include/libmaple/i2c.h @@ -37,6 +37,15 @@ extern "C" { #endif +/* + * Series header must provide: + * + * - uint32 _i2c_bus_clk(i2c_dev*): Clock frequency of dev's bus, in + * MHz. (This is for internal use only). + * + * - Reg. map base pointers, device pointer declarations. + */ + #include <series/i2c.h> #include <libmaple/i2c_common.h> @@ -212,13 +221,19 @@ static inline void i2c_write(i2c_dev *dev, uint8 byte) { /** * @brief Set input clock frequency, in MHz * @param dev I2C device - * @param freq Frequency in megahertz (2-36) + * @param freq Frequency, in MHz. This must be at least 2, and at most + * the APB frequency of dev's bus. (For example, if + * rcc_dev_clk(dev) == RCC_APB1, freq must be at most + * PCLK1, in MHz). There is an additional limit of 46 MHz. */ static inline void i2c_set_input_clk(i2c_dev *dev, uint32 freq) { +#define I2C_MAX_FREQ_MHZ 46 + ASSERT(2 <= freq && freq <= _i2c_bus_clk(dev) && freq <= I2C_MAX_FREQ_MHZ); uint32 cr2 = dev->regs->CR2; cr2 &= ~I2C_CR2_FREQ; cr2 |= freq; dev->regs->CR2 = freq; +#undef I2C_MAX_FREQ_MHZ } /** diff --git a/libmaple/stm32f1/include/series/i2c.h b/libmaple/stm32f1/include/series/i2c.h index f9f1e43..0c89df4 100644 --- a/libmaple/stm32f1/include/series/i2c.h +++ b/libmaple/stm32f1/include/series/i2c.h @@ -34,6 +34,7 @@ #define _LIBMAPLE_STM32F1_I2C_H_ #include <libmaple/i2c_common.h> +#include <libmaple/stm32.h> /* * Register maps @@ -53,4 +54,13 @@ struct i2c_reg_map; extern i2c_dev* const I2C1; extern i2c_dev* const I2C2; +/* + * For internal use + */ + +static inline uint32 _i2c_bus_clk(i2c_dev *dev) { + /* Both I2C peripherals are on APB1 */ + return STM32_PCLK1 / (1000 * 1000); +} + #endif /* _LIBMAPLE_STM32F1_I2C_H_ */ |