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-rw-r--r--sw/z80/kernel/include/devices.h13
-rw-r--r--sw/z80/kernel/include/pio.h35
-rw-r--r--sw/z80/kernel/include/types.h4
-rw-r--r--sw/z80/kernel/include/usart.h149
-rw-r--r--sw/z80/kernel/kernel.c9
-rw-r--r--sw/z80/kernel/pio.c18
-rw-r--r--sw/z80/kernel/usart.c91
7 files changed, 313 insertions, 6 deletions
diff --git a/sw/z80/kernel/include/devices.h b/sw/z80/kernel/include/devices.h
new file mode 100644
index 0000000..e8c183f
--- /dev/null
+++ b/sw/z80/kernel/include/devices.h
@@ -0,0 +1,13 @@
+#ifndef __DEVICES_H__
+#define __DEVICES_H__
+
+#define ADDR_DEV_ROM_L 0x0000
+#define ADDR_DEV_ROM_H 0x2000
+
+#define ADDR_DEV_USART 0x4000
+#define ADDR_DEV_CTC 0x4100
+#define ADDR_DEV_PIO 0x4200
+
+#define ADDR_DEV_RAM 0x8000
+
+#endif
diff --git a/sw/z80/kernel/include/pio.h b/sw/z80/kernel/include/pio.h
new file mode 100644
index 0000000..5d289ca
--- /dev/null
+++ b/sw/z80/kernel/include/pio.h
@@ -0,0 +1,35 @@
+#ifndef __PIO_H__
+#define __PIO_H__
+
+#include "devices.h"
+#include "types.h"
+
+#define PIO_A 0
+#define PIO_B 1
+
+#define PIO_MODE_0 0
+#define PIO_MODE_1 1
+#define PIO_MODE_2 2
+#define PIO_MODE_3 3
+
+#define PIO_INT_ACTIVE_HIGH (1<<5)
+#define PIO_INT_AND_MODE (1<<6)
+#define PIO_INT_ENABLE (1<<7)
+
+
+void _pio_data(int port, uint8_t data);
+void _pio_command(int port, uint8_t cmd);
+
+void pio_set_mode(int port, int mode);
+void pio_set_interrupts(int port, int control);
+void pio_set_interrupts_mask(int port, uint8_t mask);
+void pio_set_io(int port, uint8_t io);
+
+// uint8_t pio_read_data(int port);
+
+inline int pio_read_pin(int port, uint8_t pin);
+inline void pio_write_pin(int port, uint8_t pin);
+
+// TODO: implement mode (in/out/both) and interrupt vector
+
+#endif // __PIO_H__
diff --git a/sw/z80/kernel/include/types.h b/sw/z80/kernel/include/types.h
index adde214..552b7e9 100644
--- a/sw/z80/kernel/include/types.h
+++ b/sw/z80/kernel/include/types.h
@@ -1,9 +1,13 @@
#ifndef __TYPES_H__
#define __TYPES_H__
+#define register_t volatile unsigned char
+
#define int8_t char
#define uint8_t unsigned char
#define int16_t int
#define uint16_t unsigned int
+#define size_t uint16_t
+
#endif
diff --git a/sw/z80/kernel/include/usart.h b/sw/z80/kernel/include/usart.h
new file mode 100644
index 0000000..3e5c070
--- /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_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__
diff --git a/sw/z80/kernel/kernel.c b/sw/z80/kernel/kernel.c
index fe87c3d..3d5aeb6 100644
--- a/sw/z80/kernel/kernel.c
+++ b/sw/z80/kernel/kernel.c
@@ -1,10 +1,7 @@
#include "types.h"
+#include "usart.h"
-
-void main(void)
+void kmain(void)
{
- int i, j = 20;
- for (i = 0; i < 10; i++) {
- j--;
- }
+ usart_init(USART_BAUDRATE_9600, USART_PARITY_EVEN, USART_STOP_BITS_1);
}
diff --git a/sw/z80/kernel/pio.c b/sw/z80/kernel/pio.c
new file mode 100644
index 0000000..4b9caee
--- /dev/null
+++ b/sw/z80/kernel/pio.c
@@ -0,0 +1,18 @@
+#include "pio.h"
+
+static uint8_t *pio_port = (uint8_t *) ADDR_DEV_PIO;
+static uint8_t *pio_ctrl = (uint8_t *) (ADDR_DEV_PIO + 2);
+
+void _pio_data(int port, uint8_t data)
+{
+ *(pio_port + port) = data;
+}
+
+void _pio_command(int port, uint8_t cmd)
+{
+ *(pio_ctrl + port) = cmd;
+}
+
+void pio_set_mode(int port, int mode)
+{
+}
diff --git a/sw/z80/kernel/usart.c b/sw/z80/kernel/usart.c
new file mode 100644
index 0000000..9ec6dbd
--- /dev/null
+++ b/sw/z80/kernel/usart.c
@@ -0,0 +1,91 @@
+#include "usart.h"
+
+static struct _usart_device *_usart = (struct _usart_device *) ADDR_DEV_USART;
+
+void usart_set_baudrate(uint16_t baudrate)
+{
+ // enable latch access
+ _usart->LCR.divisor_latch_access = 1;
+ _usart->buffer = 0x00FF & baudrate; // LSBs
+ memcpy(&_usart->IER, &(baudrate >>8), 1);
+ // _usart->IER = 0x00FF & (baudrate >> 8); // MSBs
+ _usart->LCR.divisor_latch_access = 0;
+}
+
+void usart_set_parity(int mode)
+{
+ if (mode == USART_PARITY_EVEN) {
+ _usart->LCR.even_parity = 1;
+ }
+ else if (mode == USART_PARITY_ODD) {
+ _usart->LCR.even_parity = 0;
+ }
+
+ _usart->LCR.parity = (mode == USART_PARITY_NONE) ? 0 : 1;
+}
+
+void usart_set_stop_bits(int count)
+{
+ _usart->LCR.stop_bits = (count == USART_STOP_BITS_1) ? 0 : 1;
+}
+
+void usart_word_length(int length)
+{
+ _usart->LCR.word_length = length;
+}
+
+void usart_set_autoflow(int mode)
+{
+ _usart->MCR.autoflow = (mode == USART_AUTOFLOW_OFF) ? 0 : 1;
+ _usart->MCR.data_terminal_ready = (mode == USART_AUTOFLOW_ALL);
+}
+
+inline void usart_init(uint16_t baudrate, int parity, int stop_bits)
+{
+ usart_set_baudrate(baudrate);
+ usart_set_parity(parity);
+ usart_set_stop_bits(stop_bits);
+ usart_set_autoflow(USART_AUTOFLOW_OFF);
+}
+
+void usart_transmit(uint8_t data)
+{
+ _usart->buffer = data;
+ while (_usart->LSR.transmitter_holder_empty == 0); // wait
+}
+
+uint8_t usart_receive()
+{
+ return _usart->buffer;
+}
+
+int usart_write(uint8_t *data, size_t size)
+{
+ uint8_t *dp = data;
+
+ while (size--) {
+ _usart->buffer = *(dp++);
+ while (_usart->LSR.transmitter_empty);
+ }
+
+ // TODO: do something that actually counts for sent bytes
+ return size;
+}
+
+int usart_read(uint8_t *buffer, size_t count)
+{
+ uint8_t *bp = buffer;
+ size_t read_count = 0;
+
+ while (count--) {
+ *(bp++) = _usart->buffer;
+ // check for errors
+ if (_usart->LSR.framing_error || _usart->LSR.parity_error) {
+ bp--; // delete last byte (?)
+ } else {
+ read_count++;
+ }
+ }
+
+ return read_count;
+}
generated by cgit v1.2.1 (git 2.18.0) at 2024-06-30 21:16:23 +0200