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  • 4 weeks later...

Extender: 2x20 .1" header

RAM: AS6C4008 DIP32, DIPS2 socket, 4 10K, 1 3K3, 2 1n418 or other germanium diode, 4 position DIP switch (optional), 3V lithium battery, 1x2 jumper header, 1.uF ceramic capacitor

ROM: 32 PIN EPROM/FLASH of some type. 4 10K, 1 4position DIP switch, 3K3, the two diodes are not needed, can be replaced with 2 wires, DIP32 socket, .1uF ceramic capacitor

 

Nothing is critical on other board.

Ok, I officially don't like having 1 thread for 4 projects. icon_sad.gif These are great, and I thank brain for making this available to this 12 (too high?) person market. But I wish desperately for something more official than a forum post.

 

These BOM's don't make sense to me. And I'd like to answer go4retro's request for a review, but I'd like it to be a good review. The boards arrived quickly. look good and clean...

But, the BOM above for RAM doesn't say what the diode's should be. The ROM board doesn't have footprints for diodes, so maybe that comment belongs to the RAM board?

 

I infer from these BOMs that the things that look like surface mount pads, are just test pads?

 

Is that correct?

 

-M@

  • Like 2

On the RAM board:

R1-R4 (10K)

r5 (3K3)

r6 (6K8)

D1-2 (1n914 or similar germanium diode)

C1.1 (.1uF)

+3V (3V battery)

D1 (4 DIP switch)

IC2 (ascv61008/ascv62008/ascv64008)

 

ROM Board:

R1-R4 (10K)

r5 (3K3)

C1 (.1uF)

IC1 (27C010/27C020/27C040)

 

If you want to use SST339SF040, cut trace between pads that say "EPROM" on the bottom, and solder the pads that are on the FLASH side

 

The first batch of ROM boards had diodes, but they are not needed, so they were removed.

 

Jim

Edited by brain
  • Like 1

 

Sorry for this being slightly off topic, but do you call that a micrometer? I would have said caliper. A micrometer to me is something different.

 

gambar-mikrometer-sekrup.jpeg?resize=624

You would be correct, at least for American English. As a 10 year machinist, I know a few things :-D

 

Sorry for this being slightly off topic, but do you call that a micrometer? I would have said caliper. A micrometer to me is something different.

 

gambar-mikrometer-sekrup.jpeg?resize=624

 

Yes, it's likely years of me using an incorrect term. I'll start using Caliper. A lot of folks that I grew up around called everything a micrometer that did precision measurements, so you can blame them :)

Thank you. Please understand that I'm not complaining. I'm just curious. As a non-native English speaker it's not always so easy to know which word is the correct, or at least better, one.

But I too work in a production industry, so I can tell you that in the part of the world where the SI system rules, measurements of things like what you are talking about here are always in mm. Never cm or something else.

The caliper is in Swedish called skjutmått, which is literally sliding meter. The micrometer is called mikrometerskruv, which translates to micro meter screw. As the company where I work is producing parts with tolerances down to about 1/1000 mm, we have several tools like that.

Edited by apersson850

Thank you. Please understand that I'm not complaining. I'm just curious. As a non-native English speaker it's not always so easy to know which word is the correct, or at least better, one.

But I too work in a production industry, so I can tell you that in the part of the world where the SI system rules, measurements of things like what you are talking about here are always in mm. Never cm or something else.

The caliper is in Swedish called skjutmått, which is literally sliding meter. The micrometer is called mikrometerskruv, which translates to micro meter screw. As the company where I work is producing parts with tolerances down to about 1/1000 mm, we have several tools like that.

Yes I understand, when I was working as a machinist then, instead of developer. we would use both the English and metric systems as needed, converting between them. But in most case we would also use mm, not generally cm.

These prices are going insane. What the hey?

 

https://www.ebay.com/itm/New-Texas-Instruments-Compact-Computer-40-TI-CC-40-BASIC-Programming-NIB-Works/401469600352?epid=1936745595&hash=item5d7973f260:g:BbgAAOSwovNaSuws - $300

 

NEW in BOX RARE Vintage 1983 NOS Texas Instruments TI-CC40 Basic Pocket Computer - $315

 

Texas Instruments CC-40 Computer - $250 BIN

 

The whole 'retro computer collecting' thing is really starting to gnaw at me a bit because people are paying insane prices for things we've been dwiddling with for years. We actually use them. These folks buy them, stick them on a shelf, and we never see/hear from them again. Kind of like the guy that bought the Hexbus video adapter on eBay. We know who it is. He just doesn't respond to us. I'd love to reverse engineer that thing!

 

40 carts, $200: https://www.ebay.com/itm/Texas-Instruments-TI-99-40-Games-Cassettes-Manuals-Lot/292438695902?hash=item4416b45fde:g:qGEAAOSwAExZnizL

  • Like 1

I have to agree. Honestly, I’d like to see a viable hex-bus adapter for the 99/4A come out. I know it’s old technology compared to the nanoPEB (which I love) and the TIPI (which I am very interested in), but I’d still like to be able to hook up my CC-40 directly to my 99/4A and make productive use out of it. I suppose I could snag a hex bus RS232 if one happens to show up and hook it to the 99/4A that way, but hex bus devices in general are hard to come by.

I have to agree. Honestly, I’d like to see a viable hex-bus adapter for the 99/4A come out. I know it’s old technology compared to the nanoPEB (which I love) and the TIPI (which I am very interested in), but I’d still like to be able to hook up my CC-40 directly to my 99/4A and make productive use out of it. I suppose I could snag a hex bus RS232 if one happens to show up and hook it to the 99/4A that way, but hex bus devices in general are hard to come by.

 

I wonder what contemporary standards we will have... IF ANY going forward? I don't know what the HexBus uses, but if possible on other devices, an easily obtainable RJ45 would be nice.

From a logical point of view, it's of course possible to implement a Hex-bus interface with some I/O-bits on the TI 99/4A. If you don't have any, you could add just an input and an output latch (74LS251 and 74LS259) and a CRU interface. But would it be fast enough for the TI 99/4A to drive that in software? You, who have worked with this, are there time constraints within the Hex-bus interface that are tougher than what polling such inputs in software can handle?

  • Like 1

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