boards/nucleo-l433rc: use lpuart for stdio

- this UART is connected to st-link and can be reached via USB
    - the second UART is linked to Arduino RX/TX pins

boards/nucleo-l433rc/Makefile.dep

@@ -1 +1,3 @@
+FEATURES_REQUIRED += periph_lpuart
+
 include $(RIOTBOARD)/common/nucleo/Makefile.dep

boards/nucleo-l433rc/Makefile.features

@@ -1,5 +1,6 @@
 # Put defined MCU peripherals here (in alphabetical order)
 FEATURES_PROVIDED += periph_gpio periph_gpio_irq
+FEATURES_PROVIDED += periph_lpuart
 FEATURES_PROVIDED += periph_pwm
 FEATURES_PROVIDED += periph_rtc
 FEATURES_PROVIDED += periph_rtt

boards/nucleo-l433rc/Makefile.include

@@ -2,10 +2,5 @@
 export CPU = stm32l4
 export CPU_MODEL = stm32l433rc
 
-# stdio is not available over st-link but on the Arduino TX/RX pins
-# A serial to USB converter plugged to the host is required
-PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
-
 # load the common Makefile.include for Nucleo boards
 include $(RIOTBOARD)/common/nucleo64/Makefile.include

boards/nucleo-l433rc/include/periph_conf.h

@@ -106,6 +106,18 @@ static const timer_conf_t timer_config[] = {
  * @{
  */
 static const uart_conf_t uart_config[] = {
+    {
+        .dev        = LPUART1,
+        .rcc_mask   = RCC_APB1ENR2_LPUART1EN,
+        .rx_pin     = GPIO_PIN(PORT_A, 3),
+        .tx_pin     = GPIO_PIN(PORT_A, 2),
+        .rx_af      = GPIO_AF8,
+        .tx_af      = GPIO_AF8,
+        .bus        = APB12,
+        .irqn       = LPUART1_IRQn,
+        .type       = STM32_LPUART,
+        .clk_src    = 0, /* Use APB clock */
+    },
     {
         .dev        = USART1,
         .rcc_mask   = RCC_APB2ENR_USART1EN,
@@ -115,6 +127,8 @@ static const uart_conf_t uart_config[] = {
         .tx_af      = GPIO_AF7,
         .bus        = APB2,
         .irqn       = USART1_IRQn,
+        .type       = STM32_USART,
+        .clk_src    = 0, /* Use APB clock */
 #ifdef UART_USE_DMA
         .dma_stream = 5,
         .dma_chan   = 4
@@ -122,7 +136,8 @@ static const uart_conf_t uart_config[] = {
     }
 };
 
-#define UART_0_ISR          (isr_usart1)
+#define UART_0_ISR          (isr_lpuart1)
+#define UART_1_ISR          (isr_usart1)
 
 #define UART_NUMOF          (sizeof(uart_config) / sizeof(uart_config[0]))
 /** @} */