diff options
| author | Kevin O'Connor <kevin@koconnor.net> | 2024-09-22 21:19:59 -0400 |
|---|---|---|
| committer | Kevin O'Connor <kevin@koconnor.net> | 2024-09-22 22:14:47 -0400 |
| commit | 064eee6859e16589235fad7e425b51ade408e9bd (patch) | |
| tree | 2c153456eea2bfc1998d3124cd9b7d126c45d83e | |
| parent | 8b7cc439529d727944589b751bd3a00305976bd0 (diff) | |
| download | kutter-064eee6859e16589235fad7e425b51ade408e9bd.tar.gz kutter-064eee6859e16589235fad7e425b51ade408e9bd.tar.xz kutter-064eee6859e16589235fad7e425b51ade408e9bd.zip | |
stm32: Fix i2c clock speeds for chips with a peripheral clock over 48Mhz
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
| -rw-r--r-- | src/stm32/stm32f0_i2c.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/src/stm32/stm32f0_i2c.c b/src/stm32/stm32f0_i2c.c index 1382cd86..a45aa34b 100644 --- a/src/stm32/stm32f0_i2c.c +++ b/src/stm32/stm32f0_i2c.c @@ -148,11 +148,19 @@ i2c_setup(uint32_t bus, uint32_t rate, uint8_t addr) gpio_peripheral(ii->sda_pin, ii->function | GPIO_OPEN_DRAIN, 1); // Set 100Khz frequency and enable - i2c->TIMINGR = ((0xB << I2C_TIMINGR_PRESC_Pos) - | (0x13 << I2C_TIMINGR_SCLL_Pos) - | (0xF << I2C_TIMINGR_SCLH_Pos) - | (0x2 << I2C_TIMINGR_SDADEL_Pos) - | (0x4 << I2C_TIMINGR_SCLDEL_Pos)); + uint32_t nom_i2c_clock = 8000000; // 8mhz internal clock = 125ns ticks + uint32_t scll = 40; // 40 * 125ns = 5us + uint32_t sclh = 32; // 32 * 125ns = 4us + uint32_t sdadel = 4; // 4 * 125ns = 500ns + uint32_t scldel = 10; // 10 * 125ns = 1250ns + + uint32_t pclk = get_pclock_frequency((uint32_t)i2c); + uint32_t presc = DIV_ROUND_UP(pclk, nom_i2c_clock); + i2c->TIMINGR = (((presc - 1) << I2C_TIMINGR_PRESC_Pos) + | ((scll - 1) << I2C_TIMINGR_SCLL_Pos) + | ((sclh - 1) << I2C_TIMINGR_SCLH_Pos) + | (sdadel << I2C_TIMINGR_SDADEL_Pos) + | ((scldel - 1) << I2C_TIMINGR_SCLDEL_Pos)); i2c->CR1 = I2C_CR1_PE; } |