wip

src/usart.h

@@ -0,0 +1,46 @@
+#ifndef USART_H_
+#define USART_H_
+
+#include <inttypes.h>
+
+struct usart {
+  volatile uint32_t SR;   // Status register
+  volatile uint32_t DR;   // Data register
+  volatile uint32_t BRR;  // Baud rate register
+  volatile uint32_t CR1;  // Control register 1
+  volatile uint32_t CR2;  // Control register 2
+  volatile uint32_t CR3;  // Control register 3
+  volatile uint32_t GTPR; // Guard time and prescaler registe
+};
+
+#define USART2_BASE_ADDR (0x40004400U)
+#define USART2 ((struct usart *) USART2_BASE_ADDR)
+
+// CR Register
+// Oversampling mode
+#define USART_CR1_OVER8_BIT 15
+#define USART_CR1_OVER8_8 (1 << USART_CR1_OVER8_BIT)
+
+// USART enable
+#define USART_CR1_UE_BIT 13
+#define USART_CR1_UE_ENABLE (1 << USART_CR1_UE_BIT)
+
+// Trasmitter enable
+#define USART_CR1_TE_BIT 3
+#define USART_CR1_TE_ENABLE (1 << USART_CR1_TE_BIT)
+
+// Receiver enable
+#define USART_CR1_RE_BIT 2
+#define USART_CR1_RE_ENABLE (1 << USART_CR1_RE_BIT)
+
+// BRR Register
+#define USART_BRR_MANTISSA_BIT 4 // Bits [15:4]
+#define USART_BRR_MANTISSA_MASK (0b111111111111) // Bits [15:4]
+
+#define USART_BRR_FRACTION_BIT 0 // Bits [3:0]
+#define USART_BRR_FRACTION_MASK (0b111) // Bits [3:0]
+
+void usart2_init(void);
+void usart2_start(void);
+
+#endif