TI-99/4A Emulation on the Pocket Chip

TI99 Boot ScreenThe Pocket Chip is a neat little Linux-based computer.  I ‘bought’ one during their Kickstarter campaign, and it showed up a few weeks ago.  I wanted to see if I could install a TI99 emulator on it, and after a little bit of Googling, I found this page on the Pocket chip forums.  User romanaThree had already installed Marc Rousseau’s TI-99/Sim on their Pocket Chip.

I’m not exactly a Linux expert, but I can usually figure enough out to get whatever I’m messing around with done.  I could have just linked to romonaThree’s post, but I wanted to post a little about some of the other steps I had to go through to get this working.

TI99 Boot Screen 2

The first step was to download the arm version of TI-99/Sim.  I then needed to get the TI-99/Sim tar file over to the Pocket Chip (PC).  I already had the PC connected to my home wifi, and I needed to figure out the IP address so I could connect to it.  I opened up terminal on the PC, and typed the following:  ip addr show

I then used Putty to transfer the file over to the PC.  Once you open up Putty, you need to enter the IP address of the PC, the username (default is root), and the password (default is chip).  I used Putty to create a directory named TI99 in the usr directory, and then transferred TI-99/Sim there.

In terminal on the PC, navigate to the /usr directory.  Typing ls will give you a directory listing.  CD directory_name will change to the directory that you listed as directory_name.  To move up one directory, type CD ..

Once you’re in the TI99 directory, you unzip the tar file by typing: tar xf ti99sim-0.13.0.armhf.tar.gz

TI-99/Sim will need the TI roms.  They are in this file, which was found in The GP2X Archive on openhandhelds.org.

For cartridges, use this file.  It was found on ZX-81’s site.

When you unzipped TI99/Sim, it created a folder in the usr directory called ti99sim-0.14.0.  After unzipping the ROM and cartridge files on your computer, use PUTTY to transfer them into the /bin folder that’s located in the ti99sim-0.14.0 folder.

To run TI-99/Sim, type:

./ti99sim-sdl parsec.ctg (assuming you want to play Parsec)


Using a Gotek Floppy Emulator With HxC on My TI-99/4A – Part 2

Gotek Drive w/LCD and SwitchWhen I ordered my Gotek, the seller’s listing said that you could also order an optional LCD display for something like $7.  However, when I contacted him, he said that he was out.

I ended up ordering this basic 16×2 I2C LCD from Amazon for only about $8.

Gotek-LCDLike everything else with this little project, I had to search for the instructions on how to do this, but it was right under my nose- there was an ASCII diagram in the firmware release notes.  There was also a link to a more detailed diagram at http://hxc2001.com.


Gotek LCD

I drew up a diagram that shows just the connections shown in the ASCII version since that’s all that I needed.







Display portAll you have to do is connect the SDA and SCL pins of the LCD to the SDA and SCL pins of the J7 connector on the Gotek and add 2 pullup resistors.

The J7 connector is the display port where the LED display was already attached.  When you look at J7 straight on, SDA is the top pin, and SCL is the bottom pin.




The pullup resistors are both 4.7K and are connected between the +5V and each of the SDA and SDL lines.

A good place to access +5V is the programming port on the Gotek, which is labeled J3.

You will also need to wire the +5V and GND pins of the LCD board to the Gotek.  Again, a good place to do this is at the programing port.

LCD and Board
LCD and Board

This is my LCD after I soldered the included board onto it.  +5, GND, SDA and SCL are circled in yellow.


Gotek JA Connector
JA Connector


With a LCD installed on the Gotek, you can use it in ‘normal’ mode.  This requires a 3rd button, so you need to add one.  This is pretty easy-  all you have to do is connect a push button to the two pins of the JA connector.


You also need to copy the config file from the ‘normal mode’ folder of the firmware (Located at Config_Files\Normal_mode\HXCSDFE.CFG) to the root of your USB drive.

In normal mode, you browse forward and backwards using the original two buttons on the Gotek.  You then select the disk image that you want to load using the third button that you installed.  Normal mode also allows you to name your files anything you want- you do not have to stick to the naming convention that you had to use in ‘index mode’.

Gotek Project

This is what my Gotek looked like when I was finished.  I’m going to temporarily mount it back in the case that it came in with the LCD and new button mounted on top.  I eventually plan on moving it all into my PEB and mounting the the LCD and buttons on the front.  I’ll post some pics when I get that done.

Using a Gotek Floppy Emulator With HxC on My TI-99/4A

Gotek Floppy EmulatorI recently purchased a Gotek floppy emulator to use with my TI-99/4A.  The idea behind the emulator is to, of course, replace the floppy drive on the TI.  Well, I’m not going to physically replace the drive- I’m going to use the emulator along with my existing 5.25″ floppy drive to load programs from from disk images onto the computer.

I found a Gotek floppy emulator on Ebay that was being sold by an American seller who was licensed to install the HxC bootloader on it. Here is a link to one of his Gotek auctions.  I can’t vouch for him, but I can say that my purchase went well.  It looks like he puts a batch of emulators up for sale when he has them ready.  If the auction I linked to is over, check his other auctions.

The HxC bootloader is important because it enables you to load the HxC firmware on to it and use HFE format disk images.  The seller I bought the emulator from linked to http://hxc2001.free.fr/floppy_drive_emulator/index.html for more information about the HxC project.  When I checked that site, I was a little bit confused about what worked with the hardware that I had.  There are USB drives that connect to your PC via USB cable.  However, I had the version that uses a USB thumb drive to store the HFE disk images and move them between the PC and the Gotek.  Luckily, the seller also linked to the correct firmware that I needed to download at: http://hxc2001.com/download/floppy_drive_emulator/HXCFEUSB_HFE_beta_firmware.zip.  That file came with firmware for three different modes of use: normal, autoboot, and indexed.

Gotek HxCFor my drive with only the basic LED display, I needed to use the indexed configuration file.  After doing a full format on my thumb drive, I copied HXCSDFE.CFG from the indexed mode folder of the firmware into the root of the thumb drive.  With indexed mode, disk images have to be named in the following manner: DSKA0000.HFE, DSKA0001.HFE, DSKA0002.HFE, etc. Using the buttons on the front of the Gotek, you can page through available images and the file number is displayed on the LED as 00, 01, 02, etc until you choose the one you want.

You can download software at hxc2001.com to convert TI99 dsk images to HFE files, but to save time when I was trying to get all of this working, I just downloaded some images from whtech.com (I know that those files are from the 2014 Chicago Faire, but I’m not sure why they’re in the video directory…).  I connected the Gotek to the disk controller card in my PEB, fired it all up, and I was completely surprised that it worked like a charm!  It was a little confusing at first, but all in all, it was pretty easy.

I’ve added an optional LCD display and 3rd push button to my Gotek, but I’m going to write about that in a second post in a few days since this one has been so long.