3 files changed, 202 insertions, 0 deletions
diff --git a/system-clock/include/clock.h b/system-clock/include/clock.h
new file mode 100644
index 0000000..2ba6880
--- /dev/null
+++ b/system-clock/include/clock.h
@@ -0,0 +1,61 @@
+#ifndef CLOCK_H__
+#define CLOCK_H__
+
+#include <stdint.h>
+
+#define PERIPH_BASE    ((uint32_t)       0x40000000)
+#define AHBPERIPH_BASE (PERIPH_BASE +    0x00020000)
+#define RCC_BASE       (AHBPERIPH_BASE + 0x00001000)
+#define FLASH_R_BASE   (AHBPERIPH_BASE + 0x00003C00)
+#define PWR_BASE       (PERIPH_BASE + 0x7000)
+#define  PWR_CSR_VOSF                        ((uint16_t)0x0010)     /*!< Voltage Scaling select flag */
+
+
+#ifndef __IO
+#define __IO volatile
+#endif
+
+typedef struct {
+  __IO uint32_t cr;
+  __IO uint32_t csr;
+} pwr_t;
+
+typedef struct {
+  __IO uint32_t acr;
+  __IO uint32_t pecr;
+  __IO uint32_t pdkeyr;
+  __IO uint32_t pekeyr;
+  __IO uint32_t prgkeyr;
+  __IO uint32_t optkeyr;
+  __IO uint32_t sr;
+  __IO uint32_t obr;
+  __IO uint32_t wrpr;       
+} flash_t;
+
+typedef struct {
+  __IO uint32_t cr;
+  __IO uint32_t icscr;
+  __IO uint32_t cfgr;
+  __IO uint32_t cir;
+  __IO uint32_t ahbrstr;
+  __IO uint32_t apb2rstr;
+  __IO uint32_t apb1rstr;
+  __IO uint32_t ahbenr;
+  __IO uint32_t apb2enr;
+  __IO uint32_t apb1enr;
+  __IO uint32_t ahblpenr;
+  __IO uint32_t apb2lpenr;
+  __IO uint32_t apb1lpenr;      
+  __IO uint32_t csr;    
+} rcc_t;
+
+#define RCC (*(rcc_t*) (RCC_BASE))
+#define FLASH (*(flash_t*) (FLASH_R_BASE))
+#define PWR (*(pwr_t*) (PWR_BASE))
+
+/*
+ * Sets the system clock to a full 80Mhz.
+ */
+int set_sys_clock();
+
+#endif /* CLOCK_H__ */
diff --git a/system-clock/include/common.h b/system-clock/include/common.h
new file mode 100644
index 0000000..f58f179
--- /dev/null
+++ b/system-clock/include/common.h
@@ -0,0 +1,13 @@
+#ifndef COMMON__H
+#define COMMON__H
+
+/* Define __IO to be volatile if it's not already. */
+#ifndef __IO
+#define __IO volatile
+#endif
+
+#define bool int
+
+#define PACKED __attribute__((packed))
+
+#endif /* COMMON_H */
diff --git a/system-clock/include/gpio.h b/system-clock/include/gpio.h
new file mode 100644
index 0000000..53ece32
--- /dev/null
+++ b/system-clock/include/gpio.h
@@ -0,0 +1,128 @@
+#ifndef GPIO_H__
+#define GPIO_H__
+
+#include "common.h"
+
+#include <stdint.h>
+
+/*
+ * Possible GPIO ports.
+ */
+typedef enum {
+  GPIO_PORT_A = 0,
+  GPIO_PORT_B = 1,
+  GPIO_PORT_C = 2,
+  GPIO_PORT_D = 3
+} gpio_port_number_t;
+
+/*
+ * Structure defining the layout of the layout of the GPIO registers on the
+ * stm32l432 development board.
+ */
+typedef struct GPIO_PORT_STR {
+  __IO uint32_t mode_r;   /* Mode register */
+  __IO uint32_t pupd_r;   /* Pull up/pull down/none register */
+  __IO uint32_t speed_r;  /* Speed register */
+  __IO uint32_t type_r;   /* Type register */
+  __IO uint32_t input_r;  /* Input data register */
+  __IO uint32_t output_r; /* Output data register */
+  __IO uint32_t bsr_r;    /* Bit set/reset register */
+  __IO uint32_t lock_r;   /* Lock register */
+  __IO uint32_t altfn_r;  /* Alternate function register */
+} PACKED gpio_port_t;
+
+/*
+ * Enum defining the PINs in a GPIO port. Each port has 16 pins to use in
+ * the stm32l432.
+ */
+typedef enum GPIO_PIN_ENUM {
+  PIN_0  = 0,
+  PIN_1  = 1,
+  PIN_2  = 2,
+  PIN_3  = 3,
+  PIN_4  = 4,
+  PIN_5  = 5,
+  PIN_6  = 6,
+  PIN_7  = 7,
+  PIN_8  = 8,
+  PIN_9  = 9,
+  PIN_10 = 10,
+  PIN_11 = 11,
+  PIN_12 = 12,
+  PIN_13 = 13,
+  PIN_14 = 14,
+  PIN_15 = 15
+} gpio_pin_t;
+
+/*
+ * Enum defining the pin modes that are possible.
+ */
+typedef enum {
+  MODE_INPUT     = 0,
+  MODE_OUTPUT    = 1,
+  MODE_ALTERNATE = 2,
+  MODE_ANALOG    = 3
+} gpio_pin_mode_t;
+
+/*
+ * Enum defining the pin speeds that are possible.
+ */
+typedef enum {
+  SPEED_2MHZ = 0,
+  SPEED_10MHZ = 1,
+  SPEED_50MHZ = 3,
+} speed_t;
+
+/*
+ * Structure defining an OUTPUT pin. Structurally equivalent to the input pin,
+ * but can be used in a slightly type-safe manner.
+ */
+typedef struct {
+  __IO gpio_port_t* gpio_port;
+  gpio_pin_t pin;
+} gpio_output_pin_t;
+
+/*
+ * Sets the mode on a GPIO pin.
+ *
+ * gpio_port: the gpio port to use.
+ * pin: the pin number to set.
+ * pin_mode: the mode to set the pin to.
+ */
+void set_gpio_pin_mode(
+    __IO gpio_port_t* gpio_port,
+    gpio_pin_t pin,
+    gpio_pin_mode_t pin_mode);
+
+/*
+ * Sets the given GPIO pin to be an output pin. Returns an output_pin struct
+ * corresponding to
+ */
+gpio_output_pin_t set_gpio_pin_output(
+    __IO gpio_port_t* gpio_port,
+    gpio_pin_t pin);
+
+/*
+ * Sets an output pin on or off.
+ *
+ * pin: the pin to toggle.
+ * onoff: 0 for off, non-zero of on.
+ */
+void set_gpio_output_pin(
+    gpio_output_pin_t pin,
+    bool onoff);
+
+#define pin_on(p) \
+  set_gpio_output_pin(p, 1)
+
+#define pin_off(p) \
+  set_gpio_output_pin(p, 0)
+
+/*
+ * Enables a GPIO port and returns a reference to the register definition
+ * of that GPIO port.
+ */
+__IO gpio_port_t* enable_gpio(gpio_port_number_t number);
+
+
+#endif /* GPIO_H__ */