diff options
| -rw-r--r-- | docs/Config_Reference.md | 5 | ||||
| -rw-r--r-- | src/stm32/stm32f0_i2c.c | 7 |
2 files changed, 10 insertions, 2 deletions
diff --git a/docs/Config_Reference.md b/docs/Config_Reference.md index e4c70937..bc4dbe32 100644 --- a/docs/Config_Reference.md +++ b/docs/Config_Reference.md @@ -5001,8 +5001,9 @@ Most Klipper micro-controller implementations only support an micro-controller supports a 400000 speed (*fast mode*, 400kbit/s), but it must be [set in the operating system](RPi_microcontroller.md#optional-enabling-i2c) and the `i2c_speed` parameter is otherwise ignored. The Klipper -"RP2040" micro-controller and ATmega AVR family support a rate of 400000 -via the `i2c_speed` parameter. All other Klipper micro-controllers use a +"RP2040" micro-controller and ATmega AVR family and some STM32 +(F0, G0, G4, L4, F7, H7) support a rate of 400000 via the `i2c_speed` parameter. +All other Klipper micro-controllers use a 100000 rate and ignore the `i2c_speed` parameter. ``` diff --git a/src/stm32/stm32f0_i2c.c b/src/stm32/stm32f0_i2c.c index a45aa34b..b83ceb0f 100644 --- a/src/stm32/stm32f0_i2c.c +++ b/src/stm32/stm32f0_i2c.c @@ -153,6 +153,13 @@ i2c_setup(uint32_t bus, uint32_t rate, uint8_t addr) uint32_t sclh = 32; // 32 * 125ns = 4us uint32_t sdadel = 4; // 4 * 125ns = 500ns uint32_t scldel = 10; // 10 * 125ns = 1250ns + // Clamp the rate to 400Khz + if (rate >= 400000) { + scll = 10; // 10 * 125ns = 1250ns + sclh = 4; // 4 * 125 = 500ns + sdadel = 3; // 3 * 125 = 375ns + scldel = 4; // 4 * 125 = 500ns + } uint32_t pclk = get_pclock_frequency((uint32_t)i2c); uint32_t presc = DIV_ROUND_UP(pclk, nom_i2c_clock); |