wip why does HSE run at 16MHz?

build/main.i

@@ -2029,6 +2029,11 @@ struct rcc {
 #define RCC_CR_PLLON_ON (1 << RCC_CR_PLLON_BIT)
 
 
+#define RCC_CR_CSS_BIT 19
+#define RCC_CR_CSS_ON (1 << RCC_CR_CSS_BIT)
+
+
+
 #define RCC_CR_HSERDY_BIT 17
 #define RCC_CR_HSERDY_READY (1 << RCC_CR_HSERDY_BIT)
 
@@ -2051,6 +2056,7 @@ struct rcc {
 
 #define RCC_PLLCFGR_PLLSRC_BIT 22
 #define RCC_PLLCFGR_PLLSRC_HSE (1 << RCC_PLLCFGR_PLLSRC_BIT)
+#define RCC_PLLCFGR_PLLSRC_HSI (0 << RCC_PLLCFGR_PLLSRC_BIT)
 
 #define RCC_PLLCFGR_PLLP_BIT 16
 #define RCC_PLLCFGR_PLLP_MASK (0b11)
@@ -2070,6 +2076,19 @@ struct rcc {
 #define RCC_CFGR_PPRE_DIV_2 (0b100)
 
 
+#define RCC_CFGR_MCO1_HSI (0b00)
+#define RCC_CFGR_MCO1_HSE (0b10)
+#define RCC_CFGR_MCO1_PLL (0b11)
+
+#define RCC_CFGR_MCO1_BIT 21
+#define RCC_CFGR_MCO1_MASK (0b11)
+
+#define RCC_CFGR_MCO1PRE_DIV4 (0b110)
+
+#define RCC_CFGR_MCO1PRE_BIT 24
+#define RCC_CFGR_MCO1PRE_MASK (0b111)
+
+
 #define RCC_CFGR_PPRE2_BIT 13
 #define RCC_CFGR_PPRE2_MASK (0b111)
 
@@ -2090,6 +2109,7 @@ struct rcc {
 #define RCC_CFGR_SWS_MASK (0b11)
 
 
+#define RCC_CFGR_SW_PLL (0b10)
 #define RCC_CFGR_SW_PLL (0b10)
 
 #define RCC_CFGR_SW_BIT 0
@@ -2135,13 +2155,21 @@ struct gpio {
 #define GPIOA ((struct gpio *) GPIOA_BASE_ADDR)
 
 
-#define GPIO_MODER_MODER3_BIT 7
+#define GPIO_MODER_AF_MODE (0b10)
+
+#define GPIO_MODER_MODER8_BIT 16
+#define GPIO_MODER_MODER8_MASK (0b11)
+
+#define GPIO_MODER_MODER3_BIT 6
 #define GPIO_MODER_MODER3_MASK (0b11)
-#define GPIO_MODER_MODER3_AF (0b10)
 
 #define GPIO_MODER_MODER2_BIT 4
 #define GPIO_MODER_MODER2_MASK (0b11)
-#define GPIO_MODER_MODER2_AF (0b10)
+
+
+#define GPIO_AFRH_AFRH8_BIT 0
+#define GPIO_AFRH_AFRH8_MASK (0b1111)
+#define GPIO_AFRH_AFRH8_MCO_1 (0b0000)
 
 
 #define GPIO_AFRL_AFRL3_BIT 12
@@ -2176,9 +2204,9 @@ typedef enum {
 
 void gpio_set_mode(uint16_t pin, GPIO_MODE mode);
 void gpio_write(uint16_t pin, 
-# 64 "src/gpio.h" 3 4
+# 72 "src/gpio.h" 3 4
                              _Bool 
-# 64 "src/gpio.h"
+# 72 "src/gpio.h"
                                   val);
 # 6 "src/main.c" 2
 # 1 "src/flash.h" 1
@@ -2350,9 +2378,15 @@ static void system_clock_init(void) {
   ((struct pwr *) (0x40007000U))->CR |= ((0b11) << 14);
 
 
+  ((struct rcc *) (0x40023800U))->CR &= ~(1 << 0);
+
+
   ((struct rcc *) (0x40023800U))->CR |= (1 << 16);
 
 
+  ((struct rcc *) (0x40023800U))->CR |= (1 << 19);
+
+
 
   while (!(((struct rcc *) (0x40023800U))->CR & (1 << 17)));
 
@@ -2361,10 +2395,11 @@ static void system_clock_init(void) {
   ((struct rcc *) (0x40023800U))->CR &= ~(1 << 24);
 
 
+
   ((struct rcc *) (0x40023800U))->PLLCFGR |= (1 << 22);
 
 
-  ((struct rcc *) (0x40023800U))->PLLCFGR |= ((25 & (0b111111)) << 0) | ((196 & (0b111111111)) << 6) | ((2 & (0b11)) << 16) | ((4 & (0b1111)) << 24);
+  ((struct rcc *) (0x40023800U))->PLLCFGR |= ((25 & (0b111111)) << 0) | ((192 & (0b111111111)) << 6) | ((2 & (0b11)) << 16) | ((4 & (0b1111)) << 24);
 
 
   ((struct rcc *) (0x40023800U))->CFGR &= ~((0b1111) << 4);
@@ -2383,26 +2418,28 @@ static void system_clock_init(void) {
 
 
 
-  while (!(((struct rcc *) (0x40023800U))->CR & (1 << 17)));
+  while (!(((struct rcc *) (0x40023800U))->CR & (1 << 25)));
 
 
   ((struct flash *) (0x40023C00U))->ACR |= (1 <<10);
   ((struct flash *) (0x40023C00U))->ACR |= (1 <<9);
-
-
-  ((struct flash *) (0x40023C00U))->ACR &= ~((0b1111) << 0);
-  ((struct rcc *) (0x40023800U))->CFGR |= ((0x0111) << 0);
-
-
-  ((struct rcc *) (0x40023800U))->CFGR &= ~((0b11) << 0);
-  ((struct rcc *) (0x40023800U))->CFGR |= ((0b10) << 0);
+# 75 "src/main.c"
+  ((struct rcc *) (0x40023800U))->CFGR |= (((0b10) & (0b11)) << 0);
 
 
 
   while (((((struct rcc *) (0x40023800U))->CFGR >> 2) & (0b11)) != (0b10));
 
 
-  ((struct rcc *) (0x40023800U))->CR &= ~(1 << 0);
+
+  ((struct rcc *) (0x40023800U))->CFGR &= ~((0b11) << 21);
+
+
+  ((struct rcc *) (0x40023800U))->CFGR |= ((0b00) << 21);
+
+
+
+
 }
 
 int main(void) {
@@ -2419,20 +2456,21 @@ int main(void) {
 
   uint16_t counter = ((struct timer *) (0x40000800U))->CNT;
   
-# 90 "src/main.c" 3 4
+# 106 "src/main.c" 3 4
  _Bool 
-# 90 "src/main.c"
+# 106 "src/main.c"
       led_on = 
-# 90 "src/main.c" 3 4
+# 106 "src/main.c" 3 4
                ((_Bool)+0u)
-# 90 "src/main.c"
+# 106 "src/main.c"
                     ;
   while(1) {
+
  if ((((struct timer *) (0x40000800U))->CNT - counter) >= 250) {
   led_on = !led_on;
   gpio_write(led, led_on);
 
-  usart2_write("hello, world\n");
+ usart2_write("U\n");
 
   counter = ((struct timer *) (0x40000800U))->CNT;
  }