cores(C0): Some peripherals have HSIKER source instead of HSI

C0 doesn't have RCC_USART1CLKSOURCE_HSI
but instead RCC_USART1CLKSOURCE_HSIKER
Note: both HSI and HSIKER have the same HSI48 base,
but each have a dedicated prescaler.
This apply to UART1 and I2C1

Signed-off-by: Alexandre Bourdiol <alexandre.bourdiol@st.com>

Author: ABOSTM

cores/arduino/stm32/uart.h

@@ -88,6 +88,15 @@ struct serial_s {
 /* Exported constants --------------------------------------------------------*/
 #define TX_TIMEOUT  1000
 
+#if !defined(RCC_USART1CLKSOURCE_HSI)
+/* Some series like C0 have 2 derivated clock from HSI: HSIKER (for peripherals)
+ * and HSISYS (for system clock). But each have a dedicated prescaler.
+ * To avoid changing Arduino implementation,
+ * remap RCC_USART1CLKSOURCE_HSI to RCC_USART1CLKSOURCE_HSIKER
+ */
+#define RCC_USART1CLKSOURCE_HSI RCC_USART1CLKSOURCE_HSIKER
+#endif
+
 #if defined(USART2_BASE) && !defined(USART2_IRQn)
 #if defined(STM32G0xx)
 #if defined(LPUART2_BASE)

libraries/Wire/src/utility/twi.c

@@ -210,6 +210,11 @@ static uint32_t i2c_getClkFreq(I2C_TypeDef *i2c)
           clkSrcFreq = HSI_VALUE;
           break;
 #endif
+#ifdef RCC_I2C1CLKSOURCE_HSIKER
+        case RCC_I2C1CLKSOURCE_HSIKER:
+          clkSrcFreq = __LL_RCC_CALC_HSIKER_FREQ(LL_RCC_HSIKER_GetDivider());
+          break;
+#endif
 #ifdef RCC_I2C1CLKSOURCE_SYSCLK
         case RCC_I2C1CLKSOURCE_SYSCLK:
           clkSrcFreq = SystemCoreClock;