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Re: 8085 SBC [message #3336 is a reply to message #3318] |
Mon, 07 August 2017 14:12 |
Sergey
Messages: 236 Registered: October 2015 Location: Portland, OR
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Senior Member |
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Hi Kip,
I apologize for delayed reply. I second Gary's suggestion to double-check the handshaking/flow control settings in your terminal emulation software - make sure you have RTS/CTS flow control enabled. Otherwise you won't not able to send anything to your 8085 board, since 8251 will be waiting for the CTS signal (on 8085 board side) to become active before receiving the data.
As a quick test you might try disconnecting RTS (pin 7) and CTS (pin 8) on DE9 connector of the 8085 board from your terminal/PC, and connecting them together (kind of a RTS/CTS loopback).
While Christian is right regarding CLK frequency specifications (160 ns minimal period = 6.25 MHz), in my case 82C51A-2 works perfectly fine with 8 MHz CLK.
Best regards,
Sergey
[Updated on: Mon, 07 August 2017 14:12] Report message to a moderator
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Re: 8085 SBC [message #4777 is a reply to message #4771] |
Sun, 24 June 2018 01:07 |
b1ackmai1er
Messages: 396 Registered: November 2017
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Senior Member |
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Expensive but being sold as second hand, seller selling a range of stuff so not a business selling homebrew as a commercial venture. I don't see anything wrong with this.
Better to pass it on to someone who will use rather than sit on a shelf.
Would be interested in hearing retrobrew creators opinions.
Good reminder for me to start building mine while I wait for my ECB board parts to arrive from China - I didn't know about or remember this thread
Regards Phil.
[Updated on: Sun, 24 June 2018 01:11] Report message to a moderator
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Re: 8085 SBC [message #4789 is a reply to message #4778] |
Mon, 25 June 2018 15:56 |
Sergey
Messages: 236 Registered: October 2015 Location: Portland, OR
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Senior Member |
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Hi,
The MiniMax8085 is an open source project (and so are most of my other projects). Anyone is allowed to manufacture these designs, and sell them, be that for profit, or otherwise.
It would be nice though, if whoever is planning to mass-produce and sell PCBs, kits, or assembled boards, will contact the project author(s) and notify them. At least it would give us an opportunity to share the experience and suggestions about the project, get some idea about the interest or demand for that project, and clarify the support structure.
And by the way, a few people had approached me about selling the PCBs, or even making and selling the kits. Also, I know about several people who had manufactured and distributed some of my designs (without notifying me first). Either way, it is OK.
In this particular case, as people commented above, it doesn't look that the seller is mass-producing these boards, and likely tries to sell his own board. While the price might be higher than the price of the components, I don't see anything wrong with that. It is really up to the eBay seller to set the price.
Thanks,
Sergey
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Re: 8085 SBC [message #5190 is a reply to message #5189] |
Mon, 17 September 2018 10:23 |
Sergey
Messages: 236 Registered: October 2015 Location: Portland, OR
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Senior Member |
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Hi Rosario,
Unfortunately Chinese and Hong Kong based sellers frequently sell refurbished or relabeled parts. I personally prefer to buy locally (e.g. US sellers), or at least sellers that offer free returns/exchange.
Here are a few things I'd pay attention to when ordering ICs of the eBay:
- How the seller describes the part? "New" on a 1990's part sounds suspicious. It is possible that that some might have NOS (new old stock) parts, but they are not that common. Used/refurbished might sound more reasonable and honest. Although, I doubt a seller would have capability to test the ICs.
- Check the date code - usually a four digit number in YYWW - year/work week format. Is it too new for the part? It would be surprising to see 80C85 a part made in 2000's. Or maybe it is completely wrong, for example the work week value is above 52.
- Pay attention to the labeling. Yellowish-gray laser etched marking was not used in 1980's-1990's. If you see an older part with such marking, most likely it was relabeled.
- Parts have the same labeling, but the packages a bit differ (slightly different shape, pin 1 indent is different, the marking on the bottom are different or missing). All this is a sign of relabeling.
- Pins have signs of desoldering. They are shiny, not uniform. (New IC would have more of a flat, grayish finish).
Now, with this hobby, it is quite possible that buying ICs from China is the only choice. But at least eBay sellers are usually pretty good about returns and refunds...
BTW, maybe give this one a try: https://www.radwell.com/en-US/Buy/GENERIC/GENERIC/CA80C85B8C P
Hope this helps,
Sergey
[Updated on: Mon, 17 September 2018 15:16] Report message to a moderator
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