1 files changed, 158 insertions, 0 deletions
diff --git a/sw/z80/drivers/include/usart.h b/sw/z80/drivers/include/usart.h
new file mode 100644
index 0000000..bb06aab
--- /dev/null
+++ b/sw/z80/drivers/include/usart.h
@@ -0,0 +1,158 @@
+#ifndef __USART_H__
+#define __USART_H__
+
+#include "addresses.h"
+
+#include <stdint.h>
+#include <string.h>
+
+// baudrate clock divisors 
+// values from TL16C550C datasheet (table 9 for 1.8432 MHz crystal)
+#define USART_BAUDRATE_50       2304
+#define USART_BAUDRATE_75       1536
+#define USART_BAUDRATE_110      1047
+#define USART_BAUDRATE_134_5    857
+#define USART_BAUDRATE_150      768
+#define USART_BAUDRATE_300      384
+#define USART_BAUDRATE_600      192
+#define USART_BAUDRATE_1200     96
+#define USART_BAUDRATE_1800     64
+#define USART_BAUDRATE_2000     58
+#define USART_BAUDRATE_2400     48
+#define USART_BAUDRATE_3600     32
+#define USART_BAUDRATE_4800     24
+#define USART_BAUDRATE_7200     16
+#define USART_BAUDRATE_9600     12
+#define USART_BAUDRATE_19200    6
+#define USART_BAUDRATE_38400    3
+#define USART_BAUDRATE_56000    3
+
+// parity
+#define USART_PARITY_NONE       0
+#define USART_PARITY_EVEN       1
+#define USART_PARITY_ODD        2
+
+// stop bits
+#define USART_STOP_BITS_1       10
+#define USART_STOP_BITS_15      15
+#define USART_STOP_BITS_2       20
+
+// word lenght
+#define USART_WORD_LENGTH_5     0
+#define USART_WORD_LENGTH_6     1
+#define USART_WORD_LENGTH_7     2
+#define USART_WORD_LENGTH_8     3
+
+// autoflow
+#define USART_AUTOFLOW_ALL      3
+#define USART_AUTOFLOW_CTS      2
+#define USART_AUTOFLOW_OFF      0
+
+typedef unsigned int    uint;
+typedef uint8_t         register_t;
+
+/* stuctures for usart registers */
+struct IER 
+{
+    volatile uint received_data_interrupt :1;
+    volatile uint transmitter_empty_interrupt :1;
+    volatile uint receiver_line_status_interrupt :1;
+    volatile uint modem_status_interrupt :1;
+    volatile uint reserved :4;
+};
+
+struct IIR
+{
+    volatile uint interrupt_pending :1;
+    volatile uint interrupt_id :3;
+    volatile uint reserved :2;
+    volatile uint fifos :2;
+};
+
+struct FCR
+{
+    volatile uint fifo_enable :1;
+    volatile uint receiver_fifo_rst :1;
+    volatile uint trasmitter_fifo_rst :1;
+    volatile uint dma_mode_select :1;
+    volatile uint reserved :1;
+    volatile uint receiver_trigger :2;
+};
+
+struct LCR
+{
+    volatile uint word_length :2;
+    volatile uint stop_bits :1;
+    volatile uint parity :1;
+    volatile uint even_parity :1;
+    volatile uint stick_parity :1;
+    volatile uint break_control :1;
+    volatile uint divisor_latch_access :1;
+};
+
+struct MCR
+{
+    volatile uint data_terminal_ready :1;
+    volatile uint request_to_send :1;
+    volatile uint out1;
+    volatile uint out2;
+    volatile uint loop;
+    volatile uint autoflow :1;
+    volatile uint reserved :2;
+};
+
+struct LSR 
+{
+    volatile uint data_ready :1;
+    volatile uint overrun_error :1;
+    volatile uint parity_error :1;
+    volatile uint framing_error :1;
+    volatile uint break_interrupt :1;
+    volatile uint transmitter_holder_empty :1;
+    volatile uint transmitter_empty :1;
+    volatile uint fifo_recv_error :1;
+};
+
+struct MSR
+{
+    volatile uint delta_cts :1;
+    volatile uint delta_data_set_ready :1;
+    volatile uint trailing_edge_ring_indicator :1;
+    volatile uint delta_data_carrier_detect :1;
+    volatile uint clear_to_send :1;
+    volatile uint data_set_ready :1;
+    volatile uint ring_indicator :1;
+    volatile uint data_carrier_detect :1;
+};
+
+/* this structure is only for internal usage */
+struct _usart_device
+{
+    register_t buffer;  // also used as LSB for divisor latch
+    struct IER IER;
+    struct IIR IIR;
+    struct FCR FCR;
+    struct LCR LCR;
+    struct MCR MCR;
+    struct LSR LSR;
+    struct MSR MSR;
+    register_t scratch;
+};
+
+
+// setup functions (wrappers)
+void usart_set_baudrate(uint16_t baudrate);
+void usart_set_parity(int mode);
+void usart_set_stop_bits(int count);
+void usart_set_word_length(int length);
+void usart_set_autoflow(int mode);
+
+inline void usart_init(uint16_t baudrate, int parity, int stop_bits); 
+
+void usart_transmit(uint8_t data);
+uint8_t usart_receive();
+
+int usart_write(uint8_t *data, size_t size);
+int usart_read(uint8_t *buffer, size_t count);
+
+#endif // __USART__H__