1 files changed, 32 insertions, 6 deletions
diff --git a/02-usart/src/main.c b/02-usart/src/main.c
index 73ccb17..72b3fe7 100644
--- a/02-usart/src/main.c
+++ b/02-usart/src/main.c
@@ -3,19 +3,13 @@
 #include "core/clock.h"
 #include "core/dma.h"
 #include "core/gpio.h"
-#include "core/isr_vector.h"
 #include "core/system.h"
 #include "core/usart.h"
-
 #include "delay.h"
-#include "lib.h"
 #include "mem.h"
 #include "spin.h"
 #include "string.h"
 
-
-#ifdef ARCH_STM32L4
-
 /** Overrides the default systick irq handler. */
 void on_systick()
 {
@@ -33,12 +27,42 @@ void on_systick()
   is_on = ! is_on;
 }
 
+void setup_usart2(uint32_t baud_rate)
+{
+  __IO gpio_port_t* port_a = enable_gpio(GPIO_PORT_A);
+  enable_hsi(&RCC, true);
+
+  set_usart2_clock_src(&RCC, USART_CLK_SRC_HSI16);
+  set_usart2_clock_enabled(&RCC, USART_CLK_SRC_HSI16);
+
+  set_gpio_pin_mode(port_a, PIN_2, MODE_ALTERNATE);
+  set_gpio_pin_mode(port_a, PIN_15, MODE_ALTERNATE);
+  set_gpio_alternate_function(port_a, PIN_2, AFN_7);
+  set_gpio_alternate_function(port_a, PIN_15, AFN_3);
+
+  /* De-assert reset of USART2 */
+  regset(RCC.apb1rst1_r, rcc_usart2rst, 0);
+
+  USART2.c_r1 = 0;
+  USART2.c_r2 = 0;
+  USART2.c_r3 = 0;
+
+  usart_set_divisor(&USART2, 16000000 / baud_rate);
+}
+
+#ifdef ARCH_STM32L4
+
 /* Main function. This gets executed from the interrupt vector defined above. */
 int main()
 {
   /* Enable a higher clock frequency. */
   set_system_clock_MHz(80);
 
+  setup_usart2(115200);
+  usart_set_enabled(&USART2, USART_ENABLE_TX | USART_ENABLE_RX);
+
+  usart_printf(&USART2, "Start Configuring Countdown!\n");
+
   /* Set the countdown to start from 1,000,0000. */
   SCB.strv_r = 10000000;
 
@@ -47,6 +71,8 @@ int main()
 
   /* Start the systick. */
   SCB.stcs_bf.enable = 1;
+
+  usart_printf(&USART2, "Start Countdown Started!\n");
 }
 
 #endif