nolibgs_hello_worlds/hello_sio.c

// hello_sio example
//
// This example will display the RX data in a 64 char rolling buffer.
// 
// Use minicom or any other serial comm program and a serial/USB cable.
//
// Relevant doc is libref47.pdf, l.1120-1127
//
// Schnappy - 04/2021
//
// Based on :  ../psyq/psx/sample/serial/SIO
//
// sio echo back 
// 1.00		Jan.28.1997	shino

#include <sys/types.h>
#include <libgte.h>
#include <libgpu.h>
#include <libetc.h>
#include <stdio.h>

// Needed for SIO operations

#include <libsio.h>

// Needed for manipulating strings

#include <string.h>

// Display stuff (see hello_tile for the basics)

#define VMODE       0

#define SCREENXRES 320

#define SCREENYRES 240

#define CENTERX     SCREENXRES/2

#define CENTERY     SCREENYRES/2

#define OTLEN       2048        // Maximum number of OT entries

#define PRIMBUFFLEN 32768       // Maximum number of POLY_GT3 primitives

// Display and draw environments, double buffered

DISPENV disp[2];

DRAWENV draw[2];

u_long      ot[2][OTLEN];                   // Ordering table (contains addresses to primitives)

char    primbuff[2][PRIMBUFFLEN] = {0};     // Primitive list // That's our prim buffer

char * nextpri = primbuff[0];               // Primitive counter

short           db  = 0;                    // Current buffer counter

// SIO

#define MAX_CHARS 64

u_char SIO = 1;                             // Is SIO enabled ?

u_char SIOinit = 0;                         // Is SIO initialized ?

// Prototypes

void init(void);

void display(void);

void init(){
    
    // Reset the GPU before doing anything and the controller
    
    ResetGraph(0);
    
    // Set the display and draw environments
    
    SetDefDispEnv(&disp[0], 0, 0         , SCREENXRES, SCREENYRES);
    
    SetDefDispEnv(&disp[1], 0, SCREENYRES, SCREENXRES, SCREENYRES);
    
    SetDefDrawEnv(&draw[0], 0, SCREENYRES, SCREENXRES, SCREENYRES);
    
    SetDefDrawEnv(&draw[1], 0, 0, SCREENXRES, SCREENYRES);
    
    // If in PAL mode, add vertical offset
    
    if (VMODE)
    {
    
        SetVideoMode(MODE_PAL);
    
        disp[0].screen.y += 8;
    
        disp[1].screen.y += 8;
    }
    
    setRGB0(&draw[0], 0, 0, 255);
    
    setRGB0(&draw[1], 0, 0, 255);

    draw[0].isbg = 1;
    
    draw[1].isbg = 1;

    PutDispEnv(&disp[db]);
    
    PutDrawEnv(&draw[db]);
        
    // Init font system
    
    FntLoad(960, 0);
    
    FntOpen(16, 16, 196, 64, 0, 256);
    
    }

void display(void){
    
    DrawSync(0);
    
    VSync(0);

    PutDispEnv(&disp[db]);
    
    PutDrawEnv(&draw[db]);

    SetDispMask(1);
    
    db = !db;
    
    }

int main() {
    
    init();
    
    // Main loop
    
    while (1) {
        
        // Buffer for the RX data of size MAX_CHARS
        
        static char buffer[ MAX_CHARS ] = {0};
        
        // If SIO flag is set, initialize and get data
        
        if( SIO ){

            // Is SIO is not initialized, dot it

            if( ! SIOinit ){

                ResetCallback();
                
                // Load SIO driver at 115200bps
                
                AddSIO(115200);
                
                ResetGraph(0);
                
                // Use _sio_control to clear driver status error-related bits
                // See psyq's libref47.pdf, p.1125 for the commands and status tables
                
                _sio_control(2,1,0);
                
                SIOinit = 1;
                
            }
            
            // Limit input buffer to MAX_CHARS chars, making it a rolling buffer
            
            if( strlen(buffer) > MAX_CHARS ){
               
               // If that limit is reached, remove first char in string
               
               memmove(buffer, buffer + 1, strlen(buffer));
               
            }
            
            // Check if sio driver is able to write communications data
            // If so, this means reading is not occuring
            
            if( _sio_control(0,0,0) & SR_RXRDY ){ // SR_RXRDY == 0x2
                
                // Read byte
                
                char c = _sio_control(0,4,0);
                
                // Add to buffer
            
                strncat(buffer, &c, 1);
                
            }
            

        }           

      // END SIO FUN
        
        FntPrint("Hello Serial!\n\n");
        
        if( buffer ){
            
            FntPrint("%s", buffer);
            
        }
        
        FntFlush(-1);
        
        display();

    }
    return 0;
}