1 files changed, 102 insertions, 0 deletions
diff --git a/usart/include/usart.h b/usart/include/usart.h
new file mode 100644
index 0000000..ebc5458
--- /dev/null
+++ b/usart/include/usart.h
@@ -0,0 +1,102 @@
+#ifndef H__USART_
+#define H__USART_
+
+#include "common.h"
+#include "rcc.h"
+
+#include <stdint.h>
+
+/*
+ * Possibel USART clock sources.
+ */
+typedef enum {
+  USART_CLK_SRC_PLK = 0, /* Clock derived from the SysClk. */
+  USART_CLK_SRC_SYSCLK = 1, /* System clock. */
+  USART_CLK_SRC_HSI16 = 2, /* 16MHz oscillator. */
+  USART_CLK_SRC_LSE = 3 /* Low power 32kHz clock. */
+} usart_clk_src_t;
+
+typedef struct {
+  /* USART configuration registers 0x04 - 0x0c. */
+  uint32_t c_r1;
+  uint32_t c_r2;
+  uint32_t c_r3;
+
+  /* USART baud rate register. */
+  uint32_t br_r;
+  uint32_t gtp_r;
+  uint32_t rto_r;
+  uint32_t rq_r;
+  uint32_t is_r;
+  uint32_t ic_r;
+  uint32_t rd_r;
+  uint32_t td_r;
+} usart_t;
+
+#define USART1 (* (__IO usart_t*) 0x40013800)
+#define USART2 (* (__IO usart_t*) 0x40004400)
+typedef enum {
+  OVERSAMPLE_8,
+  OVERSAMPLE_16
+} oversampling_mode_t;
+
+static inline void usart_set_divisor(
+    __IO usart_t* usart,
+    uint32_t usartdiv)
+{
+  if (usart->c_r1 & (1 << 15)) {
+    /* OVER8 is set. */
+    usart->br_r =
+      (usartdiv & ~7) |
+      ((usartdiv & 7) >> 1);
+  } else {
+    /* OVER8 is not set. */
+    usart->br_r = usartdiv;
+  }
+}
+
+static inline void usart_set_oversampling_mode(
+    __IO usart_t* usart,
+    oversampling_mode_t mode)
+{
+  if (mode == OVERSAMPLE_8) {
+    usart->c_r1 |= 1 << 15;
+  } else {
+    usart->c_r1 &= ~(1 << 15);
+  }
+}
+
+typedef enum {
+  USART_PARITY_DISABLED = 0,
+  USART_PARITY_EVEN     = 2 << 9,
+  USART_PARITY_ODD      = 3 << 9,
+} usart_parity_t;
+
+typedef enum {
+  USART_ENABLE_TX_RX    = 0x0d, /* 0b1101 */
+  USART_ENABLE_TX       = 0x09, /* 0b1001 */
+  USART_ENABLE_RX       = 0x05, /* 0b0101 */
+  USART_ENABLE_DISABLED = 0x00, /* 0b0000 */
+} usart_enable_t;
+
+void usart_set_parity(__IO usart_t* usart, usart_parity_t parity);
+
+void usart_set_enabled(__IO usart_t* usart, usart_enable_t enabled);
+
+/*
+ * Send a byte on the usart, This command blocks until the data
+ * is fully sent.
+ */
+void usart_transmit_byte(__IO usart_t* usart, uint8_t byte);
+
+void set_usart1_clock_src(__IO rcc_t* rcc, usart_clk_src_t usart_clk_src);
+
+void set_usart1_clock_enabled(__IO rcc_t* rcc, bool enable);
+
+void set_usart2_clock_src(__IO rcc_t* rcc, usart_clk_src_t usart_clk_src);
+
+void set_usart2_clock_enabled(__IO rcc_t* rcc, bool enable);
+
+
+
+#endif /* H__USART_ */