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  #21  
Old 06-19-2008, 08:42 PM
Geoff Harrison Geoff Harrison is offline
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Quote:
Originally Posted by Grant Stockly View Post
The R/W line does not go directly from the 6800 to the motherboard.
I see. In fact I see now on the circuit diagram that the processor & motherboard R/W pins are not connected together, I didn't notice that yesterday. Sorry about that Bugman, I'm glad I didn't send you off on a wild goose chase trying to fix a problem that didn't exist.

Geoff.

Last edited by Geoff Harrison; 06-20-2008 at 01:40 AM.
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  #22  
Old 06-20-2008, 12:30 AM
Grant Stockly Grant Stockly is offline
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I think 39 of the 40 wires on the two sockets are connected together. Any time you see a signal of the same name, they are of the same "net" and are connected.
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  #23  
Old 06-20-2008, 11:42 AM
bugman bugman is offline
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No harm done. The main thing that tipped me off was when I removed the CPU, the front Panel looked exactly like my intermittent problem. Hence the CPU had intermittent connections which turned out to be a partailly seated socket.

I assembled the back cover last night. It was at that time I realized how compact this unit is. It was a tight fit! I decided to install an AC fan (despite popular suggestions!) I realize it probably isn't needed for stable operation. But I want to be able to pass this on to my kids so I'm thinking more in terms of component lifespan.

I'll start playing more around tonight. I'm anxious to use the assembler because as far as I can tell, it's the only way to output new paper tape dumps. I also want to familiarize myself with the VTL-2 and basic memory usage. With other similiar projects I have been able to identify where the data is located so I can do a raw memory save of a basic program rather that a cut and paste listing. For other computers, the paper tape read is easy to configure. But I have found that because basic and such are interpreters, they can't handle the normal transfer speed of a cut and paste directly into basic because there is a delay at the end of each line while the computer accepts the new line of code. The result is a slow transmission using that method. However, this may not be the case with the 680!

Lots of fun to be had.

Thanks for a great kit.
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  #24  
Old 06-22-2008, 01:08 AM
TomL_12953 TomL_12953 is offline
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Quote:
But I have found that because basic and such are interpreters, they can't handle the normal transfer speed of a cut and paste directly into basic because there is a delay at the end of each line while the computer accepts the new line of code. The result is a slow transmission using that method. However, this may not be the case with the 680!
I don't know about the 680 version of Microsoft BASIC but in the early 8800 versions, you can set NULL 2 or higher before writing a tape so that there will be some space added after each line. You then set the same NULL number to read the tape back. This gives the processor time to enter each line. In the later versions of MS BASIC, NULL isn't necessary. BASIC can read in the file at full speed (110 baud - Wow!) from paper tape.
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  #25  
Old 06-22-2008, 03:46 PM
bugman bugman is offline
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So far in my experimentation I am finding that I must set a line delay of about 500ms in hyperterminal to send a basic listing to microsoft basic. Not optimal, but it isn't too bad. Anything less causes corruption and the program is not entered correctly.
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  #26  
Old 06-22-2008, 03:49 PM
bugman bugman is offline
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TomL,

Are you saying there is a paper tape command within basic? For the 680, all I can find is the csave command used in the cassette version for cassette saving. I am not aware of any paper tape writing routine in 680 basic. So, I have to either paste a text listing into basic to load, or type "list" and buffer capture for save.
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  #27  
Old 06-23-2008, 02:28 AM
TomL_12953 TomL_12953 is offline
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Default No SAVE Command

Quote:
Are you saying there is a paper tape command within basic? For the 680, all I can find is the csave command used in the cassette version for cassette saving. I am not aware of any paper tape writing routine in 680 basic. So, I have to either paste a text listing into basic to load, or type "list" and buffer capture for save.
There's no paper tape SAVE command in the 8800 versions of BASIC. If you type LIST, then turn on the Teletype tape punch and press Return, the tape will be punched and contain the listing with an additional OK at the end. This can then be read into a BASIC session but will give a Syntax Error because of the OK. The entire program will be in memory, though.
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