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-rw-r--r--libmaple/usart.h88
1 files changed, 77 insertions, 11 deletions
diff --git a/libmaple/usart.h b/libmaple/usart.h
index 02fb6e0..beffa89 100644
--- a/libmaple/usart.h
+++ b/libmaple/usart.h
@@ -23,32 +23,98 @@
* ****************************************************************************/
/**
- * @file usart.h
- *
- * @brief USART Definitions
+ * @brief USART definitions and prototypes
*/
#ifndef _USART_H_
#define _USART_H_
-#define NR_USARTS 0x3
+#include "ring_buffer.h"
#ifdef __cplusplus
extern "C"{
#endif
-#define USART_MAX_BAUD 225000
+#define USART_TXE BIT(7)
+
+/* usart device numbers */
+enum {
+ USART1,
+ USART2,
+ USART3,
+};
+
+/* peripheral register struct */
+typedef struct usart_port {
+ volatile uint32 SR; // Status register
+ volatile uint32 DR; // Data register
+ volatile uint32 BRR; // Baud rate register
+ volatile uint32 CR1; // Control register 1
+ volatile uint32 CR2; // Control register 2
+ volatile uint32 CR3; // Control register 3
+ volatile uint32 GTPR; // Guard time and prescaler register
+} usart_port;
+
+/* usart descriptor */
+struct usart_dev {
+ usart_port *base;
+ ring_buffer rb;
+ uint8 rx_buf[64];
+ const uint8 rcc_dev_num;
+ const uint8 nvic_dev_num;
+};
+
+extern struct usart_dev usart_dev_table[];
+
+
+/**
+ * @brief send one character on a usart
+ * @param usart_num usart to send on
+ * @param byte byte to send
+ */
+static inline void usart_putc(uint8 usart_num, uint8 byte) {
+ usart_port *port = usart_dev_table[usart_num].base;
+
+ port->DR = byte;
+
+ /* Wait for transmission to complete */
+ while ((port->SR & USART_TXE) == 0)
+ ;
+}
+
+
+/**
+ * @brief read one character from a usart
+ * @param usart_num usart to read from
+ * @return byte read
+ */
+static inline uint8 usart_getc(uint8 usart_num) {
+ return rb_remove(&usart_dev_table[usart_num].rb);
+}
+
+
+/**
+ * @brief return the amount of data available in the rx buffer
+ * @param usart_num which usart to check
+ * @return number of bytes in the rx buffer
+ */
+static inline uint32 usart_data_available(uint8 usart_num) {
+ return rb_full_count(&usart_dev_table[usart_num].rb);
+}
+
+
+/**
+ * @brief removes the contents of the rx fifo
+ * @param usart_num which usart to reset
+ */
+static inline void usart_reset_rx(uint8 usart_num) {
+ rb_reset(&usart_dev_table[usart_num].rb);
+}
void usart_init(uint8 usart_num, uint32 baud);
void usart_disable(uint8 usart_num);
-
void usart_putstr(uint8 usart_num, const char*);
void usart_putudec(uint8 usart_num, uint32 val);
-void usart_putc(uint8 usart_num, uint8 ch);
-
-uint32 usart_data_available(uint8 usart_num);
-uint8 usart_getc(uint8 usart_num);
-void usart_clear_buffer(uint8 usart_num);
#ifdef __cplusplus
} // extern "C"