fix(core): slowdown i2c on u5 to 200kHz

[no changelog]
trezor · Apr 3, 2024 · d2aa227 · d2aa227
1 parent a1165d9
commit d2aa227
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/core/embed/trezorhal/stm32u5/i2c.c b/core/embed/trezorhal/stm32u5/i2c.c
@@ -60,8 +60,12 @@ i2c_instance_t i2c_defs[I2C_COUNT] = {
  * Using calculation from STM32CubeMX
  * PCLKx as source, assumed 160MHz
  * Fast mode, freq = 400kHz, Rise time = 250ns, Fall time = 100ns
+ * Fast mode, freq = 200kHz, Rise time = 250ns, Fall time = 100ns
+ * SCLH and SCLL are manually modified to achieve more symmetric clock
  */
-#define I2C_TIMING_400000_Hz 0x30D2153A
+#define I2C_TIMING_400000_Hz 0x30D22728
+#define I2C_TIMING_200000_Hz 0x30D2595A
+#define I2C_TIMING I2C_TIMING_200000_Hz
 
 void i2c_init_instance(uint16_t idx, i2c_instance_t *instance) {
   if (i2c_handle[idx].Instance) {
@@ -86,7 +90,7 @@ void i2c_init_instance(uint16_t idx, i2c_instance_t *instance) {
   HAL_GPIO_Init(instance->SdaPort, &GPIO_InitStructure);
 
   i2c_handle[idx].Instance = instance->Instance;
-  i2c_handle[idx].Init.Timing = I2C_TIMING_400000_Hz;
+  i2c_handle[idx].Init.Timing = I2C_TIMING;
   i2c_handle[idx].Init.OwnAddress1 = 0xFE;  // master
   i2c_handle[idx].Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
   i2c_handle[idx].Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;