From 1acafc94f40154db009d5ed55bca204c2399c0a8 Mon Sep 17 00:00:00 2001 From: yiancar Date: Thu, 31 Oct 2019 16:19:57 +0000 Subject: [PATCH] Correct ARM STM32 I2C frequency. (#7080) It was beleaved that this setting result in a 400Khz I2C bus. This was incorrect, actual frequency measure with a logic analyzer was around 150Khz. This is derived from the excel sheet linked in the .h file. Also confirmed with the ST IDE. --- drivers/arm/i2c_master.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/arm/i2c_master.h b/drivers/arm/i2c_master.h index b40fa0a910..a8ed66403a 100644 --- a/drivers/arm/i2c_master.h +++ b/drivers/arm/i2c_master.h @@ -73,19 +73,19 @@ // The default timing values below configures the I2C clock to 400khz assuming a 72Mhz clock // For more info : https://www.st.com/en/embedded-software/stsw-stm32126.html # ifndef I2C1_TIMINGR_PRESC -# define I2C1_TIMINGR_PRESC 15U +# define I2C1_TIMINGR_PRESC 0U # endif # ifndef I2C1_TIMINGR_SCLDEL -# define I2C1_TIMINGR_SCLDEL 4U +# define I2C1_TIMINGR_SCLDEL 7U # endif # ifndef I2C1_TIMINGR_SDADEL -# define I2C1_TIMINGR_SDADEL 2U +# define I2C1_TIMINGR_SDADEL 0U # endif # ifndef I2C1_TIMINGR_SCLH -# define I2C1_TIMINGR_SCLH 15U +# define I2C1_TIMINGR_SCLH 38U # endif # ifndef I2C1_TIMINGR_SCLL -# define I2C1_TIMINGR_SCLL 21U +# define I2C1_TIMINGR_SCLL 129U # endif #endif