pio.h

#ifndef _PIO_H_
#define _PIO_H_

#define SIO_TXFL    (1 << 0)    /* 1= Transmit buffer full */
#define SIO_RXRD    (1 << 1)    /* 1= Receive buffer full */
#define SIO_FRER    (1 << 2)    /* 1= Framing error occured */

#define MAX_DEVICE  2
#define DEVICE_D0   (1 << 0)
#define DEVICE_D1   (1 << 1)
#define DEVICE_D2   (1 << 2)
#define DEVICE_D3   (1 << 3)
#define DEVICE_TL   (1 << 4)
#define DEVICE_TR   (1 << 5)
#define DEVICE_TH   (1 << 6)
#define DEVICE_ALL  (DEVICE_D0 | DEVICE_D1 | DEVICE_D2 | DEVICE_D3 | DEVICE_TL | DEVICE_TR | DEVICE_TH)

#define PIN_LVL_LO  0       /* Pin outputs 0V */
#define PIN_LVL_HI  1       /* Pin outputs +5V */
#define PIN_DIR_OUT 0       /* Pin is is an active driving output */
#define PIN_DIR_IN  1       /* Pin is in active-low input mode */

enum {
    PORT_A          = 0,    /* I/O port A */
    PORT_B          = 1     /* I/O port B */
};

enum {
    DEVICE_NONE     = 0,    /* No peripheral */
    DEVICE_PAD2B    = 1,    /* Standard 2-button digital joystick/gamepad */
    DEVICE_PADDLE   = 2     /* Paddle controller; rotary dial with fire button */
};

typedef struct {
    uint8 tr_level[2];  /* TR pin output level */
    uint8 th_level[2];  /* TH pin output level */
    uint8 tr_dir[2];    /* TR pin direction */
    uint8 th_dir[2];    /* TH pin direction */
} io_state;

/* Global variables */
extern io_state io_lut[2][256];
extern io_state *io_current;

/* Function prototypes */
void pio_init(void);
void pio_reset(void);
void pio_shutdown(void);
void system_assign_device(int port, int type);

void io_lut_init(void);
void ioctrl_w(uint8 data);
uint8 input_r(int offset);
void sio_w(int offset, int data);
uint8 sio_r(int offset);

#endif /* _PIO_H_ */