Step 1: Understand the QT2 Hardware

First, determine:

    Main MCU (likely a TI MSP430, STM32, or an Atmel chip like ATmega/ATSAM)

    Display type (likely an SPI or parallel monochrome LCD)

    Keyboard matrix layout (rows × cols)

    Flash/RAM specs

    Power/clock source

    Existing debug interfaces (UART? SWD? USB?)

🛠 You may need to:

    Open the QT2 to identify components

    Use a logic analyzer to trace LCD, keypad, or flash bus

    Search FCC/Teardown sites for schematics or part numbers

📦 Step 2: Compare to SRXE

The existing BASIC port is tightly coupled to the Smart Response XE, which has:

    ATmega128RFA1

    ST7586 LCD

    10×6 key matrix

    SPI flash storage

You'll need to rewrite low-level hardware interfacing for:

    LCD output

    Keyboard input

    (optional) Flash storage I/O

But you can reuse:

    The Tiny BASIC interpreter core

    The main loop and I/O abstraction model

🔄 Step 3: Port Steps

    Replace hardware drivers

        Implement lcd_init(), lcd_putchar(), and screen clear/update routines for QT2 LCD

        Scan and debounce QT2’s keyboard matrix (rewrite keyboard.c)

        Stub or replace SPI flash functions (optional)

    Adapt the build system

        Choose the right MCU architecture

        Replace AVR-GCC with ARM-GCC / MSP430-GCC depending on QT2's chip

        Create a new Makefile or use PlatformIO

    Redirect input/output

        Rewrite BASIC's print_char() and get_char() to use your new drivers

        Optionally include UART for debug

    Tune memory use

        Ensure QT2 has enough RAM for the interpreter and program buffer

        Possibly reduce array or string storage size

🔌 Step 4: Get Firmware on the QT2

You’ll need:

    A programming interface: JTAG, SWD, or ISP depending on the chip

    A way to flash firmware: ST-Link, MSP430 Launchpad, USBasp, etc.

You might also want to:

    Backup existing firmware before erasing

    Probe for bootloader if present

🧠 Summary
Task	Difficulty	Notes
Identify QT2 chip & peripherals	🟨 Medium	Requires opening device & probing
Rewriting drivers (LCD, keyboard)	🟥 Hard	If no datasheets or known LCD type
Adapting Tiny BASIC core	🟩 Easy	Interpreter is portable
Building & flashing	🟨 Medium	Depends on chip and access
✅ Recommendation

Before writing code:

    Crack open the QT2 and take high-res photos of the PCB

    Identify the main chip and LCD driver

    Trace the keyboard matrix lines

    Share what you find — I can help build a hardware abstraction layer tailored to it