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-rw-r--r--sw/z80/kernel/include/usart.h149
1 files changed, 149 insertions, 0 deletions
diff --git a/sw/z80/kernel/include/usart.h b/sw/z80/kernel/include/usart.h
new file mode 100644
index 0000000..f1f428e
--- /dev/null
+++ b/sw/z80/kernel/include/usart.h
@@ -0,0 +1,149 @@
+#ifndef __USART_H__
+#define __USART_H__
+
+#include "types.h"
+#include "devices.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
+
+
+/* this structure is only for internal usage */
+struct _usart_device
+{
+ register_t buffer; // also used as LSB for divisor latch
+
+ struct IER
+ {
+ volatile int received_data_interrupt :1;
+ volatile int transmitter_empty_interrupt :1;
+ volatile int receiver_line_status_interrupt :1;
+ volatile int modem_status_interrupt :1;
+ volatile int reserved :4;
+ } IER;
+
+ struct IIR
+ {
+ volatile int interrupt_pending :1;
+ volatile int interrupt_id :3;
+ volatile int reserved :2;
+ volatile int fifos :2;
+ } IIR;
+
+ struct FCR
+ {
+ volatile int fifo_enable :1;
+ volatile int receiver_fifo_rst :1;
+ volatile int trasmitter_fifo_rst :1;
+ volatile int dma_mode_select :1;
+ volatile int reserved :1;
+ volatile int receiver_trigger :2;
+ } FCR;
+
+ struct LCR
+ {
+ volatile int word_length :2;
+ volatile int stop_bits :1;
+ volatile int parity :1;
+ volatile int even_parity :1;
+ volatile int stick_parity :1;
+ volatile int break_control :1;
+ volatile int divisor_latch_access :1;
+ } LCR;
+
+ struct MCR
+ {
+ volatile int data_terminal_ready :1;
+ volatile int request_to_send :1;
+ volatile int out1;
+ volatile int out2;
+ volatile int loop;
+ volatile int autoflow :1;
+ volatile int reserved :2;
+ } MCR;
+
+ struct LSR
+ {
+ volatile int data_ready :1;
+ volatile int overrun_error :1;
+ volatile int parity_error :1;
+ volatile int framing_error :1;
+ volatile int break_interrupt :1;
+ volatile int transmitter_holder_empty :1;
+ volatile int transmitter_empty :1;
+ volatile int fifo_recv_error :1;
+ } LSR;
+
+ struct MSR
+ {
+ volatile int delta_cts :1;
+ volatile int delta_data_set_ready :1;
+ volatile int trailing_edge_ring_indicator :1;
+ volatile int delta_data_carrier_detect :1;
+ volatile int clear_to_send :1;
+ volatile int data_set_ready :1;
+ volatile int ring_indicator :1;
+ volatile int data_carrier_detect :1;
+ } MSR;
+
+ register_t scratch;
+};
+
+
+// setup functions (wrappers)
+void usart_set_baudrate(uint16_t baudrate);
+void usart_set_parity(int mode);
+void usart_set_stob_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__