Hugo Cervantes

Greetings. Thanks for sharing these games for the TI-74. I have downloaded almost all of them. However, although some are quite small (just like Numbers here), I am not able to run on my TI-74 because I get the MEMORY FULL and/or BAD PROGRAM TYPE errors. Of course I have changed the .txt extension to null or .c74, but this does not fix the issue. It seems the TI-74 detects your programs were created using a TI-74 with the Memory Extension cartridge. I don't have it... Could that be the issue? If so, could you publish here your programs as ASCII text files? I may copy then and have them running on my device... Any other suggestions? Thanks !

Can’t remember if someone here showed what is required to connect a TI-40 or TI-74 to a VGA or any other kind of external display. I just watched a nice implementation for the HP-71b to be connected via WiFi to an iPad... In case some of you are interested, here is the link: wouldn’t it be nice implementing something like this for our old loved TI’s?

Thanks Peter. Unfortunately don’t have a RAM Module for the TÍ-74. I also read somewhere somebody building those as it is nearly impossible getting one these days. Any experience on that? I think the fake model that comes with each TI-74 could be adapted to store the EPROM and battery...

After successful implementation of the SD storage solution for CC-40 and TI-74 I was wondering, have some of the experts here (Jim Brain, Peter Engels, etc.) implemented a replacement solution for the TI-74 Pascal Module (TI-74 Cartridge "LEARN PASCAL”)? Beyond Basic, I would love using the SD solution for storing/testing with Pascal programs and data files. I remember reading some time ago (although can’t remember where) about someone sharing the original IT Learn Pascal cartridge image, so that it could be copied/used on a compatible EPROM for the TI-74 expansion slot. Any ideas/suggestions? Thanks!

Hello Wolfgang, Go for it!! It is really not that hard to implement, and you will get lots of fun and interesting working hours with your TI-74 once you have a program/data storage solution. I can help with any questions that you may have, and for sure Jim and other experts here will be happy to assist as well. Good luck!

I am happy to share with you another successful implementation of Jim Brain’s Arduino-Based SD Storage Solution, for a Texas Instruments TI-74 BasiCalc. Main differences on my project are: 1) I was not able to get/buy an Arduino-UNO SD Card Logging Recorder DataLogger ModuleShield, so I am using the standard Arduino SD Card Module. 2) This is for a Ti-74, therefore I am implementing for a Dockbus (10-pin) port instead of the CC40 Hexbus (8-pin) port. Points to consider: 1) The standard Arduino SD Card Module DOES NOT have an integrated clock; DOES NOT have/support as well Card Detect and Write Protect pins. Fortunately this can be solved (as per Jim’s great support/advice) by simply connecting Digital pins 8 and 9 at the Arduino Uno card to ground. With this, both functions return present and non-write protected all the time. 2) Obviously, all programs and other files will be saved to the SD card with no date/time stamp, which is not a major issue, but with the advantage that latest code, shared by Jim at Github (HEXTIr version 0.9.3.2), does not require any modifications to be complied on the Arduino, and successfully run for a TI-74 connected to it. 3) I used Arduino IDE version 1.8.13 4) There was an old Fritzing diagram showing wiring for the standard Arduino SD card module, BUT it was outdated and had some errors/omissions. Please check attached here a new version, showing updated required grounding and pin assignments. 5) I started by implementing my prototype on a breadboard (see attached picture). Once correct functionality was confirmed, I migrated it to a regular Arduino Protoshield Borad (see attached picture) for the final version. 6) Trying to emulate a bit the Logging Recorder DataLogger ModuleShield, I glued the Arduino Standard CD Module to the Arduino Protoshield Borad. 6) So far, I have successfully tested OLD, SAVE, RUN, VERIFY and LIST using a standard SD card formatted to FAT32. Hope this may help others willing to replicate.

Jim, sent you last night some pics and info via email. Just would like to confirm if you received. Tks!!

Still not good luck... I think part of the problem could be my dockbus wiring as I am not using any converter. Could I send you directly (trying not to saturate this forum) by email or other method some pics of my wiring? My email is hugoc57@hotmail.com. I activated as suggested the debug option, but not getting more information than this when entering SAVE "100.TEST" at my TI-74... which may indicate an issue with wiring, right?

Thanks again for your quick reply... still no luck. I found/commented "#define INCLUDE_CLOCK" as indicated. The only change I noticed is I am getting now E0 I/O ERROR 255 "100". It wouldbe great if you are able to test this latest version on your board as I am almost sure my circuit is fine according with your diagram for SC card. Thanks!

Thanks again Jim. I succesfully implemented the diagram circuit (image above), including ground connection for pins 8 & 9 as you suggested. I was able as well to flash my Arduino UNO with the latest SRC.INO with no problem, so I tested it after connecting my TI-74 with the ribbon cable. Unfortunately I am not able yet to save/load programs. After typing SAVE "100.TEST" with a small program loaded, I am getting E0 I/O ERROR 39 "100". Any ideas/suggetions? During my troubleshooting, I tested my SD card reader with basic Arduino libraries and it works fine (read/write files), so that's not the issue. I tried as well to turn the clock function off (as you indicated on your comment above), however, I was not able to find CONFIG_CLOCK=1 in config.h. Should I look somwhere else? Thanks again for your comments and suggestions. I think I am pretty close to get this working! Hugo

Hey Jim, thanks for your update on this. I am almost ready to start the implementation of the Arduino-based interface for my TI-74. However I have a problem: I have not been able to get the Arduino Data Logger Extension card, but I have the smaller, Micro SD Card Reader generic module. While looking at the documentation provided at your GitHub, I just found under HEXTIr/pcb/Fritzing/ the attached image, showing implementation with this SD card reader. Could I use it instead of the Data Logger following the connection diagram provided there, and if so, would I have to change and/or use a different *.ino program (under HEXTIr/src/) to flash the Arduino UNO from my Windows laptop? Thanks in advance! Hugo

Hi Meinhard, I am extremely interested on replicating your nice and smart solution for the TI-74 Mass Storage Device. Did you have a chance to organize and share your project? Otherwise perhaps some basic wiring/circuit diagram and Arduino coding would be enough? Thanks in advance!

Hi Jeff, Amazing work on creating the interface!! Couple of questions: 1) For those of us with only a regular cassette tape recorder, would that work on, let´s say, manual mode? 2) I recently read about a TI Connectivity USB cable for their latest Graph Calculators (TI-73, TI-83, TI-83 Plus, etc). Do you think there could be a chance for adapting one of those to the TI-74, 95? Thanks! Hugo