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                               ▒▒ɱ▒5
                                    He▒▒▒▒World

/*
* =================================================================================
* Interactive Serial "Hello World" for Casio fx-9860G
* =================================================================================
*
* Description:
* This Add-In sends "Hello World" over the serial port (2.5mm TRS jack).
*
* Instructions:
* - Run the Add-In from the main menu.
* - Press [F1] to send the "Hello World" message.
* - Press [EXE] to close the serial port and exit the application.
*/

#include "fxlib.h"
#include <string.h>

/*
* =================================================================================
* Serial Syscall Definitions
* =================================================================================
* The standard fx-9860G SDK does not provide C headers for the serial port.
* We define them here using a C-based stub that calls the OS routines directly.
*/

/**
* @brief Syscall 0x0418: Opens the serial port with the given configuration.
*/
const unsigned int sc_serial_open[] = { 0xD201D002, 0x422B0009, 0x80010070, 0x0418 };
typedef int (*sc_serial_open_t)(unsigned char*);
#define Serial_Open ((sc_serial_open_t)sc_serial_open)

/**
* @brief Syscall 0x040E: Puts one byte into the serial transmit buffer.
* This is inspired by the Serial_BufferedTransmitOneByte example in the forum post.
*/
const unsigned int sc_serial_write_byte[] = { 0xD201D002, 0x422B0009, 0x80010070, 0x040E };
typedef int (*sc_serial_write_byte_t)(unsigned char);
#define Serial_WriteByte ((sc_serial_write_byte_t)sc_serial_write_byte)

/**
* @brief Syscall 0x0419: Closes the serial port.
*/
const unsigned int sc_serial_close[] = { 0xD201D002, 0x422B0009, 0x80010070, 0x0419 };
typedef int (*sc_serial_close_t)(int);
#define Serial_Close ((sc_serial_close_t)sc_serial_close)


/*
* =================================================================================
* Main Application
* =================================================================================
*/

// Global flag to track the serial port status
int g_is_port_open = 0;

/**
* @brief Sends the "Hello World" string character by character.
*/
void SendHelloWorld(void) {
    const char* message = "Hello World\n";
    int i;

    if (!g_is_port_open) {
        locate(1, 4);
        Print((unsigned char*)"Error: Port is not open!  ");
        Bdisp_PutDisp_DD();
        return;
    }

    for (i = 0; i < strlen(message); ++i) {
        Serial_WriteByte(message[i]);
    }
    
    locate(1, 4);
    Print((unsigned char*)"Sent: 'Hello World'      "); // Pad with spaces to clear previous messages
    Bdisp_PutDisp_DD();
}

int AddIn_main(int isAppli, unsigned short OptionNum)
{
    unsigned int key;
    unsigned char serial_config[] = {0, 5, 0, 0, 0, 0}; // 9600 baud, 8N1

    Bdisp_AllClr_DDVRAM();
    locate(1, 1);
    Print((unsigned char*)"Serial Communication Demo");
    locate(1, 2);
    Print((unsigned char*)"-----------------------");
    locate(1, 6);
    Print((unsigned char*)"[F1] Send 'Hello World'");
    locate(1, 7);
    Print((unsigned char*)"[EXE] Exit");
    
    // Attempt to open the serial port
    if (Serial_Open(serial_config) == 0) {
        g_is_port_open = 1;
        locate(1, 4);
        Print((unsigned char*)"Serial port opened.");
    } else {
        g_is_port_open = 0;
        locate(1, 4);
        Print((unsigned char*)"Error: Failed to open port");
    }
    Bdisp_PutDisp_DD();

    // Main event loop
    while(1)
    {
        GetKey(&key);
        if (key == KEY_CTRL_F1) {
            SendHelloWorld();
        }
        else if(key == KEY_CTRL_EXE) {
            break;
        }
    }

    // Close the port before exiting
    if (g_is_port_open) {
        Serial_Close(1);
    }

    return 1;
}

#pragma section _BR_Size
unsigned long BR_Size;
#pragma section

#pragma section _TOP
int InitializeSystem(int isAppli, unsigned short OptionNum)
{
    return INIT_ADDIN_APPLICATION(isAppli, OptionNum);
}
#pragma section

/*
* =================================================================================
* ESP32 Receiver for Casio fx-9860G Serial Communication
* =================================================================================
* Description:
* This code listens for serial data from a Casio calculator on HardwareSerial port 2.
* It's configured for 9600 baud, 8N1, to match the calculator's settings.
*/

// Define the pins for the secondary serial port (Serial2)
#define CALC_RX_PIN 16 // GPIO 16
#define CALC_TX_PIN 17 // GPIO 17

void setup() {
  Serial.begin(115200);
  
  // Initialize the secondary serial port to communicate with the calculator
  // Baud Rate: 9600
  // Config: SERIAL_8N1 (8 data bits, No parity, 1 stop bit)
  // Pins: RX on GPIO 16, TX on GPIO 17
  Serial2.begin(9600, SERIAL_8N1, CALC_RX_PIN, CALC_TX_PIN);

  Serial.println("\nESP32 Serial Receiver Initialized");
  Serial.println("---------------------------------");
  Serial.print("Listening on GPIO ");
  Serial.print(CALC_RX_PIN);
  Serial.println(" at 9600 baud...");
  Serial.println("Waiting for message from Casio calculator...");
}

void loop() {
  // Check if there is data available from the calculator
  if (Serial2.available()) {
    // Read the incoming byte from the calculator and write it to the Serial Monitor
    char receivedChar = Serial2.read();
    Serial.print(receivedChar);
  }
}