casioserial 0.1.0

Serial protocol library and CLI for Casio fx-series calculators (fx-9750G PLUS and relatives)

casioserial

Transfer programs and pictures between a computer host and a CASIO fx-series graphing calculator over its 3-pin serial link.

It comes in two parts:

• casiocom — a command-line tool for transfers. If you just want to copy .g1m files to and from your calculator, start here.
• casioserial — the Python library casiocom is built on, for scripting transfers or building your own tooling.

Tested against the CASIO fx-9750G PLUS and fx-9860G Slim models. Other fx-series models that use the same link protocol should work.

Install

pip install casioserial

Using the casiocom CLI

casiocom is installed alongside the library.

Send a g1m file to the calculator

Put the calculator into receive mode (MENU → LINK → RECEIVE), then:

casiocom -d /dev/ttyAMA0 transmit PROJECT.g1m

Send only specific items, by their title inside the container:

casiocom -d /dev/ttyAMA0 transmit PROJECT.g1m PROG1 PICT5

Overwrite items that already exist on the calculator:

casiocom -d /dev/ttyAMA0 transmit -f PROJECT.g1m

Receive a g1m file from the calculator

Start the receiver, then put the calculator into send mode (MENU → LINK → TRANSMIT):

casiocom -d /dev/ttyAMA0 receive BACKUP.g1m

Use -f to overwrite an existing output file.

Flags

Flag	Default	Meaning
-d, --device	/dev/ttyAMA0	Serial device
-b, --baudrate	9600	Baud rate
--stopbits	1	Stop bits (1 or 2)
--verbose	off	Print protocol and g1m parsing detail
-f, --force	off	Overwrite existing items / the output file

The baud rate, parity and stop bits must match the calculator's communication settings. The defaults (9600 baud, 1 stop bit) match the calculator's factory settings.

Example session

$ casiocom -d /dev/ttyAMA0 transmit SCUM2.g1m
Establishing serial communication with Casio serial device (/dev/ttyAMA0)
Serial communication is established
Transmitting program SCUM 2.0 (4724B)
Transmitting program SETPSCUM (632B)
Transmitting program SUB (3296B)
Ending serial communication with Casio serial device (/dev/ttyAMA0)

Add --verbose to see every packet on the wire and per-item detail — including when an item is skipped because it already exists (re-run with -f to overwrite it).

Using the library

from casioserial import CasioSerialDevice, Program, g1mfile

# Read programs out of a .g1m container
with g1mfile.G1mFile('SCUM2.g1m', 'r') as g:
    programs = [item for item in g.itemlist()
                if isinstance(item, g1mfile.G1mProgram)]

# Transmit them to a connected calculator (must be in LINK → RECEIVE)
with CasioSerialDevice(mode='transmit', device='/dev/ttyAMA0') as dev:
    dev.start_communication()
    for prog in programs:
        dev.transmit_program(
            Program(name=prog.g1m_title,
                    data=prog.g1m_program,
                    password=prog.g1m_password),
            overwrite=False,
        )
    dev.end_communication()

G1mFile is a context manager that opens and closes the file; CasioSerialDevice is a context manager that opens and closes the serial port. casioserial.SerialCommunicationException is raised on protocol errors.

In receive mode, receive_item() returns Program and Picture objects (and None once the transfer is finished); transmit_program() and transmit_picture() take those same objects.

The cable

The calculator uses a 3-pole 2.5 mm jack (the SB-62 port). It speaks plain asynchronous serial at logic levels, so a 3.3 V UART (e.g. the GPIO UART on a Raspberry Pi, or a 3.3 V USB-to-TTL adapter) can talk to it directly:

  Host UART (3.3 V)                  Casio SB-62 jack (2.5 mm, 3-pole)
  ─────────────────                  ─────────────────────────────────
  GND ───────────────────────────────  Sleeve   (ground)
  TXD ───────────────────────────────  Ring     (calculator RX)
  RXD ───┬──[ 100Ω ]─────────────────  Tip      (calculator TX)
         │
         └──[ 220Ω ]──▶│── GND        (▶│ can be an LED to GND)

Point -d/--device at whichever host serial port you wire up (/dev/ttyAMA0, /dev/ttyUSB0 etc.).

To drive the calculator from a PC's RS-232 COM port instead, you need a MAX232 to shift the ±12 V RS-232 levels down to logic level. A clear DB9/MAX232 build writeup is here https://www.petervis.com/electronics%20guides/Casio%20Serial%20Cables/Casio%20Serial%20Cable%20Circuit%20Build.html

Supported items

• Programs — transmit and receive.
• Pictures — transmit and receive (stored in the g1m as 128×128 bitmaps).
• Other item types found in a g1m container are skipped with a warning.