"My first design before I decided to use the BS-2 was to come out of the c=64 into an ULN2803 then go into PS2502-4{Photo Darlington & Transistor / Detector) then go into an 74LS240"
I think that every time you add an unnecessary transistion, you risk deteriorating the signal. Keep it simple and right.
Going through the 74LS240 or the 74LS244 offers you protection with just one transistion. It does not require much current at all [noparse][[/noparse]maybefar less than 1ma]. I suspect no current limiting resistors are need. It also eliminates the question of two isolated power supplies [noparse][[/noparse]due to the opto isolation] and the issue of whether you need to boost the c+64 output to drive the opto-isolators LED.
The BasicStamp can easily handle direct connection to the 74LS series.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Tom Walker said...
Chris,
Two weeks ago I gave away a full set of TechDocs and an SX-64...someone with an idea for using Commodores in FIRST robotics...small world. I do still have a "bug-tray-box" full of '64 and Amiga support chips, though. Wonder if they're worth anything?
Right now the most sought after chip for Commodore is the 6581 (SID) chip.· It was a common failure and hard to find.· Of the few C=64s I had that weren't working when I got rid of them almost every one had a bad SID chip.· The Power Supply was the other common problem.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Chris Savage Parallax Tech Support csavage@parallax.com
Chris,
Two weeks ago I gave away a full set of TechDocs and an SX-64...someone with an idea for using Commodores in FIRST robotics...small world. I do still have a "bug-tray-box" full of '64 and Amiga support chips, though. Wonder if they're worth anything?
Right now the most sought after chip for Commodore is the 6581 (SID) chip. It was a common failure and hard to find. Of the few C=64s I had that weren't working when I got rid of them almost every one had a bad SID chip. The Power Supply was the other common problem.
Hmmm, I have 4 LARGE boxes of C64's old and newer models, plus a LOT of books/programs/accessories, and a FIXABLE
SX64. There HAS to be a lot of good parts, on the non-working units, plus there are 2 or 3 working 64's and a printer, several drives
ect... Make me an offer plus shipping...
Kramer is right...Direct connection to 74LSxxx or 74HCxxx is not a problem.· The transceiver (74LS245) circuit I built connected to the Cartridge Port, NOT the User Port.· It actually used the higher address lines available there with some logic to select the interface.· This was very similar to how the Stereo SID Chip modification worked.· In fact a few of us made our own bootable cartidges at one point, but didn't have anything really useful to anyone else.· Oh, the problem with the power supplies was that C= didn't want end-users servicing/repairing these or anyone to know what was in there so they filled them with epoxy.· This caused overheating problems.· One of the things my business sold was repairable upgrade supplies (Which to my knowledge never needed repair).·
Robert,
·· It's great that you still have a bunch of stuff...If I still had some I would donate it but I already did that twice in the past so I am empty.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Chris Savage Parallax Tech Support csavage@parallax.com
I just checked my parts box and the only chip that I have available now is the 54LS240. full #[noparse][[/noparse]F 54LS240DMQB]
8431
INDONESIA
As far as I remember, when I ordered it I ordered the 74LS240.
I think I remember reading some where that these chips are the same except one is military grade.
I'm not presently at my home right now. It will be about 7 or 8 weeks before I get there and most of my data books as well as most of my parts are there. But I have the c=64 and the BS-2 and the super carrier board.
If I can use this chip I'd liked to try and put this together and start learning the BS-2 programming.
In regards to the comments that Tom and Robert posted, I'll save your post in my documents and when I'm ready to get more parts I'll let you know, when I find you on the forum. I am planning to get some more c=64s but it will be a few months after I move.
Allie,
I usually Google for the PDFs of each component. You can do it directly to verify the 54ls240 is the same.
One of the most wonderful things about the internet is that I don't have a huge library of data books [noparse][[/noparse]I did years ago].
Military Spec is usually a better quality version of the same item [noparse][[/noparse]tighter quality control, better operating temperature, more precise].
At this point, I would just be searching, reading and researching these details for you. It is better if you can learn to locate and read the info for your self. After all, if you don't verify what I say, you might not notice something I overlooked or misunderstood.
And Chris, it appear the 74HC may NOT work as the trigger is 1/2 supplly voltage, must use a 74HCT. Still the HC and HCT may not handle the slow edges of the C=64 very well in certain cases.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
·Hi every one, · · Could some one please·let me know what state the P0-P7 and P8-P15 I/O pins assume on power up·on BS2. ·I tried to find this on the parallex's CD which came with my BS-2. But I can't find where it is on the CD.
They all 'reset' to an 'INPUT' state. I'm not sure if the 'high' or 'low' state is all set to 'low', or just left alone. But the "INPUT" state makes them all 'high-impedance', until a 'HIGH' or 'LOW' command is issued for that pin.
Hi Allie,
If you don't have a copy, download a free one from the parallax website: "Basic Stamp Syntax and Reference Manual". It's available as a pdf file, and rather that print it, you can browse for what you need. The information you request is on page 83 of mine. http://www.parallax.com/detail.asp?product_id=27218
It's a great resource!
Jim
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In the end, it seems that it's all about getting the LEDs to blink....
I probably should use seperate power supplies for this and just tie the vss lines together. It would be better protection for BS-2 because the C=64 is known to have power supply problems and put out a higher voltage.
A question about the count statement Input and output. My Commodore 64 outputs a low negative transition on its handshaking line called PC2 when it goes low for one clock cycle (of 1us) when port B is written or read.
The flag (input line only) looks for a negative sensitive input. The diagram in the Commodore 64 interfacing blue book by V.J.GEORGIOU shows the PC2 line as Min. of 0.5us output and the FLAG2 input line as ~10us and shows a square wave.
I would say that I will have to use external hardware to stretch the PC2's (1us) to the BASIC STAMP'S COUNT command which requires a (2us) signal.
Two questions
(1) Do I sound right about stretching the PC2's (1us) pulse?
(2) Can the BASIC STAMP 2'S COUNT command use this negative going pulse [noparse][[/noparse]input and output] or does it have to be inverted to a positive pulse?
The only part that I have to stretch this pulse is the SN7432N [noparse][[/noparse]QUAD OR GATE]. THE FORREST MIMS ENGINEER'S NOTEBOOK shows me a circuit for this with the 7402/74LS02 [noparse][[/noparse]QUAD NOR GATE].
If I come out of the C=64's PC2'S line, then go into the 54LS240 [noparse][[/noparse]OCTAL BUFFER] which will invert the negative transition signal to a positive signal, then go into the PULSE STRETCHER CIRCUIT would the BS-2 be o.k. with this. Where as the PC2'S signal started out with a negative transition from the C=64 and the circuits above inverted it will it be necessary to re-invert it back to a negative signal for the C=64 to work right.
What do you mean a low negative [noparse][[/noparse]-0.5 volts or less]?
Technically, the BS can handle that, but that is about all. {I would avoid putting anything below 0 into the BS}
It would probably be best to clamp the negative voltage to nearly zero by providing a clamping diode somewhere on the I/O.
Another approach would have to be created if you need to use that negative signal. I suspect you could invert it with a transitor.
You can attach your signature automatically to all post. It really doesn't matter as the left hand box has your name too.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
I believe they mean from +5 volts to 0 volts. The PC2 line is held high at +5 volts until it does it's pulse of (1us). Then it goes back to the +5 volts, until the next time the port is read or written to.
···········___________····_______________+5 volts
low going pulse ---->|_|<---0.5 us min.
The diagram in the interfacing book show's a 0.5 us min. pulse. In the text of the book it say's there is a 1 us pulse.
·I am using the BASIC STAMP 2. I checked the books that I downloaded from PARALLAX'S web site and I think that the POLLIN command isn't listed for the BASIC STAMP 2. ·So I will stretch the .05us PC2 pulse and leave it inverted to a high pulse for the BS-2 to read. If I'm wrong please let me know.
·I found the old post on the site you mentioned, along with lots of other places which I'll be checking out.
·I'm not sure if I can still stay on this thread as it's been so long. There is info here someone may want to refresh up on for answering new questions. Please let me know if I need to start a new thread as this was never closed.
Comments
I think that every time you add an unnecessary transistion, you risk deteriorating the signal. Keep it simple and right.
Going through the 74LS240 or the 74LS244 offers you protection with just one transistion. It does not require much current at all [noparse][[/noparse]maybe far less than 1ma]. I suspect no current limiting resistors are need. It also eliminates the question of two isolated power supplies [noparse][[/noparse]due to the opto isolation] and the issue of whether you need to boost the c+64 output to drive the opto-isolators LED.
The BasicStamp can easily handle direct connection to the 74LS series.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Post Edited (Kramer) : 2/22/2006 6:27:39 AM GMT
Something like this -- other guys are better at it than I am.
I didn't use insert here and the image changed some.
2N222
+ ____________
.···· ················· \|_________ BasicStamp Pin #1
_ ____________/|
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Post Edited (Kramer) : 2/21/2006 3:53:09 PM GMT
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Hmmm, I have 4 LARGE boxes of C64's old and newer models, plus a LOT of books/programs/accessories, and a FIXABLE
SX64. There HAS to be a lot of good parts, on the non-working units, plus there are 2 or 3 working 64's and a printer, several drives
ect... Make me an offer plus shipping...
Bob N9LVU
Robert,
·· It's great that you still have a bunch of stuff...If I still had some I would donate it but I already did that twice in the past so I am empty.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com
I just checked my parts box and the only chip that I have available now is the 54LS240. full #[noparse][[/noparse]F 54LS240DMQB]
8431
INDONESIA
As far as I remember, when I ordered it I ordered the 74LS240.
I think I remember reading some where that these chips are the same except one is military grade.
I'm not presently at my home right now. It will be about 7 or 8 weeks before I get there and most of my data books as well as most of my parts are there. But I have the c=64 and the BS-2 and the super carrier board.
If I can use this chip I'd liked to try and put this together and start learning the BS-2 programming.
In regards to the comments that Tom and Robert posted, I'll save your post in my documents and when I'm ready to get more parts I'll let you know, when I find you on the forum. I am planning to get some more c=64s but it will be a few months after I move.
allie
I usually Google for the PDFs of each component. You can do it directly to verify the 54ls240 is the same.
One of the most wonderful things about the internet is that I don't have a huge library of data books [noparse][[/noparse]I did years ago].
Military Spec is usually a better quality version of the same item [noparse][[/noparse]tighter quality control, better operating temperature, more precise].
At this point, I would just be searching, reading and researching these details for you. It is better if you can learn to locate and read the info for your self. After all, if you don't verify what I say, you might not notice something I overlooked or misunderstood.
And Chris, it appear the 74HC may NOT work as the trigger is 1/2 supplly voltage, must use a 74HCT. Still the HC and HCT may not handle the slow edges of the C=64 very well in certain cases.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Thanks.
I went to jameco's web site and got specs for 74ls240 but couldn't find 54ls240. So I'll try google next.
allie
The 54LS has a wider operating temperature and it also sinks/sources less current than the 74LS.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
· Thank's for your input.
· I went google searching and found specs for 54ls240 and compaired them to 74ls240. Specs seem to be o.k.· ·for this chip.
· Chris
· Thank's for your input. Now it's time for me to wire this up. I'll let you's know, how it goes.
· Regards
· Allie from north eastern Canada (Nova Scotia)
·
· Could some one please·let me know what state the P0-P7 and P8-P15 I/O pins assume on power up·on BS2.
·I tried to find this on the parallex's CD which came with my BS-2. But I can't find where it is on the CD.
·Thank you.
· Allie
If you don't have a copy, download a free one from the parallax website: "Basic Stamp Syntax and Reference Manual". It's available as a pdf file, and rather that print it, you can browse for what you need. The information you request is on page 83 of mine.
http://www.parallax.com/detail.asp?product_id=27218
It's a great resource!
Jim
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
In the end, it seems that it's all about getting the LEDs to blink....
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com
I probably should use seperate power supplies for this and just tie the vss lines together. It would be better protection for BS-2 because the C=64 is known to have power supply problems and put out a higher voltage.
Allie
A question about the count statement Input and output. My Commodore 64 outputs a low negative transition on its handshaking line called PC2 when it goes low for one clock cycle (of 1us) when port B is written or read.
The flag (input line only) looks for a negative sensitive input. The diagram in the Commodore 64 interfacing blue book by V.J.GEORGIOU shows the PC2 line as Min. of 0.5us output and the FLAG2 input line as ~10us and shows a square wave.
I would say that I will have to use external hardware to stretch the PC2's (1us) to the BASIC STAMP'S COUNT command which requires a (2us) signal.
Two questions
(1) Do I sound right about stretching the PC2's (1us) pulse?
(2) Can the BASIC STAMP 2'S COUNT command use this negative going pulse [noparse][[/noparse]input and output] or does it have to be inverted to a positive pulse?
The only part that I have to stretch this pulse is the SN7432N [noparse][[/noparse]QUAD OR GATE]. THE FORREST MIMS ENGINEER'S NOTEBOOK shows me a circuit for this with the 7402/74LS02 [noparse][[/noparse]QUAD NOR GATE].
If I come out of the C=64's PC2'S line, then go into the 54LS240 [noparse][[/noparse]OCTAL BUFFER] which will invert the negative transition signal to a positive signal, then go into the PULSE STRETCHER CIRCUIT would the BS-2 be o.k. with this. Where as the PC2'S signal started out with a negative transition from the C=64 and the circuits above inverted it will it be necessary to re-invert it back to a negative signal for the C=64 to work right.
Sorry for not signing of on the bottom of the last post but I mistakenly hit the wrong key and things took of on me.
Thanks in advance
Regards allie
Technically, the BS can handle that, but that is about all. {I would avoid putting anything below 0 into the BS}
It would probably be best to clamp the negative voltage to nearly zero by providing a clamping diode somewhere on the I/O.
Another approach would have to be created if you need to use that negative signal. I suspect you could invert it with a transitor.
You can attach your signature automatically to all post. It really doesn't matter as the left hand box has your name too.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
I believe they mean from +5 volts to 0 volts. The PC2 line is held high at +5 volts until it does it's pulse of (1us). Then it goes back to the +5 volts, until the next time the port is read or written to.
···········___________····_______________+5 volts
low going pulse ---->|_|<---0.5 us min.
The diagram in the interfacing book show's a 0.5 us min. pulse. In the text of the book it say's there is a 1 us pulse.
Hope this helps.
regards allie
Post Edited (allie) : 3/3/2006 9:04:19 AM GMT
PBasic has a command called POLLIN that you may want to use.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
·So I will stretch the .05us PC2 pulse and leave it inverted to a high pulse for the BS-2 to read. If I'm wrong please let me know.
allie
·
You are correct, the BS-2 does not support any of the polling commands. Only the BS-2p modules support polling.
Regards,
Bruce Bates
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Thank you for the reply. I'll use the COUNTIN command.
allie
·I found the old post on the site you mentioned, along with lots of other places which I'll be checking out.
·I'm not sure if I can still stay on this thread as it's been so long. There is info here someone may want to refresh up on for answering new questions. Please let me know if I need to start a new thread as this was never closed.
·Thank you
·allie