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Topic: Cassette Interface firmware available soon (Read 1284 times) |
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Trash80toG-4
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WHOOOSSSSHHHHH! !!!!!!
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Re: Cassette Interface firmware available soon
« Reply #15 on: Dec 2nd, 2003, 1:10pm » |
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on Sep 21st, 2003, 6:38am, vbriel wrote:
I consider this a major breakthrough since I was getting hammered for not having the ability to store programs on the Replica I.
Stay tuned.... more to follow in the next week or two.
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Criminy  . . . talk about being impatient! How much time do those complainers think the woz had a/o took to add tape storage after the original A1 started selling like hotcakes?
You're doing this on the side and somebody is complaining that you've only managed to ship a functional CPU replica so far!?! 
Kudos, Vince! 
jt
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iceandfire
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Re: Cassette Interface firmware available soon
« Reply #16 on: Dec 2nd, 2003, 1:41pm » |
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Congrats, Vince,
We're all anxious for a cassette interface so we can trade programs, load old programs saved 25 years ago, and save those "new" programs we're playing with now. It's great having the non-volitile memory (and lots of it), but I'm getting a large collection on RAM of stuff that needs to be saved eventually. The cassette interface will solve those problems for us. I don't want Vince to feel "hammered" by requests, and in fact I think he is a godsend to those of us that are interested in the Apple-I but didn't have a way to re-visit the old memories with actual play-time. I for one do not have the skills and abilities needed to create hardware like this. I dare say that's true for most of us.
Keep up the good work.
Larry
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Larry Nelson
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vbriel
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Re: Cassette Interface firmware available soon
« Reply #17 on: Dec 2nd, 2003, 2:07pm » |
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on Dec 2nd, 2003, 1:10pm, Trash80toG-4 wrote:
Criminy . . . talk about being impatient! How much time do those complainers think the woz had a/o took to add tape storage after the original A1 started selling like hotcakes?
You're doing this on the side and somebody is complaining that you've only managed to ship a functional CPU replica so far!?!
Kudos, Vince!
jt |
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Well, in all fairness I have it posted on my web site "coming soon" and I never try and lead people on. Larry chose the NV-RAM option until the cassette interface is done. I too have programs I'd like to post for everybody and it will get there. Time is the issue and as long as orders keep pooring in I must comit to those first. I will however work top priority on both the cassette and the serial I/O and if I get both going at the same time maybe I'll just make it a combo board as the big cost is the blank boards.
It's won't be long now. Cheers 
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vbriel
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Re: Cassette Interface firmware available soon
« Reply #18 on: Dec 5th, 2003, 6:24pm » |
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Ok, I changed the 74HC74 for a 74LS74 as was used in the original cassette interface and now the sound is loud and clear on the tape. However I've been unable to load from tape yet. Adjusting the volume does change the results though so I know I'm close. At high volume I get constant "AA"'s in all the memory locations and it ends the reading process early. Turning it too low and it doesn't read anything and never comes out of read mode. Somewhere in the middle I can get data but it is wrong. Not sure if any of what I'm trying to read is actual code or garbage.
I am using one other IC with a slight variance and that is the 74LS10. My local electronics store only had 7410's so I'll order the LS series online and see if I get different results.
This brings back 20 year old nightmares of trying endlessly to load from tape. I knew starting on the cassette interface that the load process was going to be the hard part as the circuit must decode sounds into 1's and 0's. With a little good luck I may have more good news in a week or less.
If I get a chance, I'll upload the recording I made. It's basic E000-EFFF and I'm trying to load it at 7000-7FFF.
I will also double check my EPROM code on the cassette interface for errors but I think it's good.
Anybody with analog circuit experience wanna jump in on this one?
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Mage66
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Re: Cassette Interface firmware available soon
« Reply #19 on: Dec 29th, 2003, 11:13am » |
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I remember in the old days, we used to have something called a "Winky Board", I used to have one on my TRS-80 and my Timex/Sinclair 2068 that would clean up the cassette signal and help it load better.
Also, we used to be good at aligning the cassette head by ear using a small screwdriver.
The brand of tape recorder used to matter too!
Any chance of you getting a TRS-80 Tape Recorder or an old Sony?
You don't want a player with Automatic Gain (I believe), LORD! It's been a long time...
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iceandfire
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Re: Cassette Interface firmware available soon
« Reply #20 on: Dec 29th, 2003, 12:33pm » |
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The Apple I was so cranky  that tapes recorded on one cassette player would often not read back with a different player. And yes, the Winky-boards, Brand, volume, tone etc. changed the chances of getting a good tape.
With all that, I think I will do like most of the Replica owners, and send the data directly to my laptop, save it as a wave file (or MP3) and just play it back to the Replica when I need it. It's easy to make a CD from those files too, for hard-copy backups.
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Larry Nelson
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vbriel
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Re: Cassette Interface firmware available soon
« Reply #21 on: Dec 29th, 2003, 1:14pm » |
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on Dec 29th, 2003, 11:13am, Mage66 wrote:
The brand of tape recorder used to matter too!
Any chance of you getting a TRS-80 Tape Recorder or an old Sony?
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Have one, CCR-81 (the white one) and that's what I'm using for my testing. The noise is due to terrible AT power supplies. Had I thought that one through a little more I wouldn't have used it but ATX is probably just as noisey. I wanted a supply that everyone could find, cheap, and didn't involve tearing apart a perfectly good Apple II. That given, once I solve the read function I recomend going with something like a II or IIGS power supply. Voltages required for the replica are 5V, -12V, GND. The -12V is required only for Apple II keyboards and the cassette interface.
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Mage66
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Re: Cassette Interface firmware available soon
« Reply #22 on: Dec 29th, 2003, 3:36pm » |
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on Dec 29th, 2003, 1:14pm, vbriel wrote:
Have one, CCR-81 (the white one) and that's what I'm using for my testing. The noise is due to terrible AT power supplies. Had I thought that one through a little more I wouldn't have used it but ATX is probably just as noisey. I wanted a supply that everyone could find, cheap, and didn't involve tearing apart a perfectly good Apple II. That given, once I solve the read function I recomend going with something like a II or IIGS power supply. Voltages required for the replica are 5V, -12V, GND. The -12V is required only for Apple II keyboards and the cassette interface. |
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Is there any chance of putting filter caps or something on the AT Power Supply to clean it up a bit?
I'd have to buy a Power Supply, or wait until Trenton in April or May to get an old Apple II for $5.00 to strip for it.
But maybe that's the best thing, as I could use the case, keyboard and such to case it up...
Hmm..... LOL!
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vbriel
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Re: Cassette Interface firmware available soon
« Reply #23 on: Dec 29th, 2003, 4:51pm » |
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Sure, actually I think the noise is coming from the internal fan. I'd say just open it up and unhook it but I'll test out more once I can read from tapes. I do get varied responses when changing playback volume. For example, high volume I get all "AA" in the memory locations I'm trying to restore. Too low of volume and I never get the prompt back (endless search), and somewhere in the middle I get junk with no memory cells being correct. I might try my laptop for a recorder just to see if maybe it is my recorder causing the problem.
Remember, the ASCII keyboard must be from a II or IIplus not a IIe. The IIe was the matrix section only, no encoding onboard.
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