fabrice montupet Posted February 16, 2017 Share Posted February 16, 2017 My 99/8 computer has a low serial number (#22), it didn't received the Pascal GROM/ROM Kit.I would like to try this feature. As it will be difficult to find a ROM/GROM Kit, I would like to make my own. No chance for me to produce a GROM, so my idea is to make a hardware GROM simulator that will use EPROM chips and that will use the less component that it is possible to make smallest PCBs. The goal is to install onto the 99/8 motherboardNo need to reinvent the wheel. So, before starting the developpment,I would like to know if someone has already made a GROM simulator that has the abilty to manage 10 GROMs.Of course, I read many years ago the excelent book of Mike Bunyard about the TI-99 hardware and I was very interested by the GROM simulator that he proposed. But it is only for a 6Kb GROM chip. It could be a start for build my own simulator .It seems to me that an article about the GROM simulation has been published in the German TI-Revue but I haven't found it.Do you have any information? Thanks by advance 2 Quote Link to comment Share on other sites More sharing options...
brain Posted February 16, 2017 Share Posted February 16, 2017 THere are a numberr of options, including VHDL, Verilog, and C code (AVR). But, the big question is: how many GROM bases? I assume 2 bases of 5 GROMs each, but perhaps I am wrong. JIm Quote Link to comment Share on other sites More sharing options...
fabrice montupet Posted February 16, 2017 Author Share Posted February 16, 2017 I haven't begun the study of all the P-System GROMs. But, yes, 5 GROMs per base is normaly the norm. I forgot to mention an important pre-requisite : Not to disfigure the 99/8, I will use only technology that was used in 1983 ( at the 99/8 period). So no Atmel and all other things like that. 1 Quote Link to comment Share on other sites More sharing options...
+mizapf Posted February 16, 2017 Share Posted February 16, 2017 (edited) The maximum memory as shown in MAME: https://github.com/mamedev/mame/blob/master/src/mame/drivers/ti99_8.cpp Speech: TMS5200C, a rare variant of the TMS52xx family. Compatible to the speech data for the separate speech synthesizer for the TI-99/4A. Speech ROMs CD2325A, CD2326A (total 128K*1) ROM: TMS4764 (8K*8 ), called "ROM0" in the specifications [1] TMS47256 (32K*8 ), called "ROM1" [1] TMS47128 (16K*8 ), "P-Code ROM" (only available in late prototypes) See below for contents GROMs: TI-specific ROM circuits with internal address counter and 6 KiB capacity (see grom.c) 3 GROMs (system GROMs, access via port at logical address F830) 8 GROMs (Pascal / Text-to-speech GROMs, port at logical address F840) 8 GROMs (Pascal GROMs, port at logical address F850) 3 GROMs (Pascal GROMs, access via port at logical address F860) (total of 132 KiB GROM) RAM: 1 TMS4016 (SRAM 2K*8 ) 8 TMS4164 (DRAM 64K*1) (I HATE these silly smileys that show up e.g. when you have an 8 and a closing parenthesis) Edited February 16, 2017 by mizapf 1 Quote Link to comment Share on other sites More sharing options...
fabrice montupet Posted February 16, 2017 Author Share Posted February 16, 2017 The 99/8 P-System GROM Kit contains 3 PCB ("A" that contains 4 GROMs, "B" that contains 2 GROMs and "C" that contains 4 GROMs) So according to the PCBs configuration, I can see 3 GROM base. Quote Link to comment Share on other sites More sharing options...
+mizapf Posted February 16, 2017 Share Posted February 16, 2017 If I remember correctly they piggy-backed GROMs. Quote Link to comment Share on other sites More sharing options...
fabrice montupet Posted February 16, 2017 Author Share Posted February 16, 2017 Oh! Interesting! I never saw that!On the five or six 99/8 computers equiped with P-System that I know, I don't remember seeing one with piggy-backed P-System GROMs. All of them has the same kit (3 PCB totalizing 10 GROMs) pluggable on the motherboard. Quote Link to comment Share on other sites More sharing options...
+mizapf Posted February 16, 2017 Share Posted February 16, 2017 Whatever way they were organized, we have genuine dumps of a total of 22 GROMs from Ciro's console. Maybe he can have a look inside how they look like. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted February 17, 2017 Share Posted February 17, 2017 They are stacked on both of my 99/8s. . .boards "A" and "C" have 8 GROMs each. Quote Link to comment Share on other sites More sharing options...
fabrice montupet Posted February 17, 2017 Author Share Posted February 17, 2017 I would be happy to see pictures of them.I know that such boards have been made ("8GROM" is written on my 99/8 motherboard top silk, near board "A" location ) but I never saw them. Quote Link to comment Share on other sites More sharing options...
Tursi Posted February 18, 2017 Share Posted February 18, 2017 My AVR code can handle 15 (8k) GROMs in a single ATMEGA1284 (120k total). It's glueless - you can connect it directly to the GROM bus, and pretty easy to change the mapping for whatever layout you need. http://harmlesslion.com/software/ubergrom Quote Link to comment Share on other sites More sharing options...
fabrice montupet Posted February 18, 2017 Author Share Posted February 18, 2017 Your UberGROM using the ATMEGA1284 is a really a great work, but I wish my project uses more age-old components. 2 Quote Link to comment Share on other sites More sharing options...
HackMac Posted April 29, 2017 Share Posted April 29, 2017 It seems to me that an article about the GROM simulation has been published in the German TI-Revue but I haven't found it. Do you have any information? Hi Fabrice, Did you already find the TI-Revue articles? I found an article in TI-Revue 5/85, where Heiner Martin published his his GROM module (8k GROM + 8k ROM) schematics and the PCB. Additionally there are articles in TI-Revue 6/87 (which resides in the magazine HCA). Reiner Zigler tells us there how to build a module expander (a small hardware which generates additional GROM base addres select lines) and how to expand the previously mentioned GROM module to 40k GROM. Do you need these articles? Quote Link to comment Share on other sites More sharing options...
fabrice montupet Posted May 1, 2017 Author Share Posted May 1, 2017 Hi Henrik :-) Alas, I haven't find the TI-Revue articles and I would be very happy to read what you've found! Thank you by advance! Quote Link to comment Share on other sites More sharing options...
Flottmann1 Posted May 2, 2017 Share Posted May 2, 2017 (edited) from the TI-REVUE_1985-05 I have this ROM/GROM Cartridge, her some Picture and it works fine Edited May 2, 2017 by Flottmann1 4 Quote Link to comment Share on other sites More sharing options...
mantadoc Posted May 2, 2017 Share Posted May 2, 2017 I got these made , works great so far 7 Quote Link to comment Share on other sites More sharing options...
Flottmann1 Posted May 3, 2017 Share Posted May 3, 2017 (edited) Hi Fabrice, Did you already find the TI-Revue articles? I found an article in TI-Revue 5/85, where Heiner Martin published his his GROM module (8k GROM + 8k ROM) schematics and the PCB. Additionally there are articles in TI-Revue 6/87 (which resides in the magazine HCA). Reiner Zigler tells us there how to build a module expander (a small hardware which generates additional GROM base addres select lines) and how to expand the previously mentioned GROM module to 40k GROM. Do you need these articles? I have the TI Part from the German Magazin HCA as PDF Scan here HCA_1987_8.pdf Edited May 3, 2017 by Flottmann1 1 Quote Link to comment Share on other sites More sharing options...
etownandy Posted May 4, 2017 Share Posted May 4, 2017 Not to stray too far OT, but...it makes me wonder about the GROM box TI was taking around to state fairs back in the day. A fair number of unreleased module dumps came our way because they were being shown on these boxes. Quote Link to comment Share on other sites More sharing options...
fabrice montupet Posted May 4, 2017 Author Share Posted May 4, 2017 Thank you Flottmann1 :-) I am going to read it with a great pleasure! Quote Link to comment Share on other sites More sharing options...
+acadiel Posted May 4, 2017 Share Posted May 4, 2017 Not to stray too far OT, but...it makes me wonder about the GROM box TI was taking around to state fairs back in the day. A fair number of unreleased module dumps came our way because they were being shown on these boxes. Ksarul is now in possession of the two that I had. I have pictures on http://www.hexbus.comof them Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted May 5, 2017 Share Posted May 5, 2017 I have two of the CEC9914 GROM boxes, along with one of the pizza-box GSIM devices (and a lot of disks for it), an EGROM Box, and a GSIM that was modified by TI to become a prototype Plato module. . . 4 Quote Link to comment Share on other sites More sharing options...
HackMac Posted May 6, 2017 Share Posted May 6, 2017 Thank you Flottmann1 :-) I am going to read it with a great pleasure! Sorry Fabrice, for my late response, but Flottmann was too "flott" (German slang word for hurry) for me (like back the years in school: "hmmm, hmmm, take me...! I know it better...") :-) If you still miss some information, just ask... I only have my weekends to be TI-active... 2 Quote Link to comment Share on other sites More sharing options...
Artoj Posted December 6, 2023 Share Posted December 6, 2023 Hi All, I am not sure why the 74LS139 pins 4/5/6/7 are not connected to anything and what I can figure they are for adding RAM (6264) on pin 20 (CE#). Can anyone who reads German or who has built the circuit let me know. Regards Arto. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted December 7, 2023 Share Posted December 7, 2023 7 hours ago, Artoj said: Hi All, I am not sure why the 74LS139 pins 4/5/6/7 are not connected to anything and what I can figure they are for adding RAM (6264) on pin 20 (CE#). Can anyone who reads German or who has built the circuit let me know. Regards Arto. Here is a quick translation of the two paragraphs that discuss the ROM and GROM selection circuitry. Note that the pins you are looking at here are not normally used unless trying to decode the ROM space into 2K chunks. . . Martin Board.odt 2 Quote Link to comment Share on other sites More sharing options...
Artoj Posted December 7, 2023 Share Posted December 7, 2023 37 minutes ago, Ksarul said: Here is a quick translation of the two paragraphs that discuss the ROM and GROM selection circuitry. Note that the pins you are looking at here are not normally used unless trying to decode the ROM space into 2K chunks. . . Martin Board.odt 22.94 kB · 0 downloads Thank you for the prompt reply, I find it curious that this was never explained clearly. I am looking into the GROM circuitry so I can start to write software. What I have gathered so far, is TI created a system that can run programs with a minimum of RAM and a maximum of control. The only loss was speed and a slight increase of complexity. The GPL language is an amazing journey and Speccery has unlocked a lot of it's potential. I am looking forward to applying this knowledge into programming. Thanks Ksarul for you insight, regards Arto. 2 1 Quote Link to comment Share on other sites More sharing options...
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