The Internet – On A Casio Calculator!

Over the years we’ve become used to seeing some impressive hacks of high-end calculator software and hardware, most often associated with the Z80-based models from Texas Instruments. But of course, TI are far from the only player in this arena. It’s nice for a change to see a Casio receiving some attention. The Casio fx series of graphical calculators can now communicate with the world, thanks to the work of [Manawyrm] in porting a TCP/IP stack to them.

As can be seen in the video below, lurking in the calculator’s menu system is an IRC client, there is also a terminal application and a webserver which you can even visit online (Please be aware that it’s only a calculator though, so an onslaught of Hackaday readers clicking the link may bring it down). The Casio doesn’t have a network interface of its own, so instead, it speaks SLIP over the serial port. In this endeavor, it uses a UART driver sourced from [TobleMiner].

It’s always good to see a neglected platform get some love, and also to note that this is an unusual outing for an SH4 CPU outside its most familiar home in the Sega Dreamcast. It’s a surprise then to read that the SH4 in a calculator of all products, is a custom version that lacks an FPU. This deficiency doesn’t mean it can’t be overclocked though, as this very old Hackaday article describes.

12 thoughts on “The Internet – On A Casio Calculator!

    1. I didn’t know of SLIP until recently when I had to implement it in a project. At first I thougt it felt like a stoneage protocol, but then I got to appreciate its simplicity. And it gets the job done. :)

  1. In 1979, someone I knew was upgrading a record factory. Intersil 6100 since it was like a PDP/8, to replace mechanical timing. But for programming, he had a little terminal, I have no idea what brand (I don’t think I knew) that was the size of a calculator. I guess more buttons, and a serial interface.

  2. I did something similar back in the late 90’s with a TI-92 graphing calculator, the Fargo assembly shell w/ a terminal program, external modem + home made DB25 null modem gender changer + TI Graph link cable, and a dial up shell with my ISP at the time and an IRC program on the shell. Could have done other things as well in the shell. Yes it wasn’t TCP/IP internet on the calculator but got access to the internet none the less through it.

  3. >It’s a surprise then to read that the SH4 in a calculator of all products, is a custom version that lacks an FPU.

    You don’t want the usual IEEE floating point math in a calculator as they are inexact.
    You want to use BCD math and FPU won’t help.

  4. We are currently working on another calculator, hp 39gii, to rewrite its operating system completely(Based on freeRTOS and will soon switched to nuttX, for better support of mmu, probably).
    Link: https://github.com/Repeerc/ExistOS-For-HP39GII

    It have a powerful arm processor up to 400MHz, USB 2.0 High speed, 128MB SLC NAND flash.
    But the mmu inside the SoC is… hard to deal with. Still a long way to go.

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