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No, not on the road. On the address bus or data bus.
Bus collisions happen when outputs of two different chips output a different signal to the same line of the bus. It's a short circuit which can easily fry one or both outputs, ruining one or both chips involved.
The solution? Like on a busy intersection where two roads cross: A traffic light, plus some bus drivers which always cut off one side of the intersection while opening up the other at the same time. This way a 'red light' could not be ignored, even if it accidentally happened.
What I need that for? I'm building a single board computer to try some things out. It will get plenty of RAM (at least 1 Mb), a CDP1802 BCE processor at 5 MHz, traditional bit banged RS232 serial I/O and a MC6847 graphics chip with all the display memory it can handle and above mutual exclusion device to allow both the CPU and the MC6847 to access the display memory.
The sad thing is that the whole thing will be obsolete once it works, because my goal is to build a even better 'old computer' and wanted to have some things worked out before trying to tackle everything at once.
Unless... Would it not be great if the single board computer became the graphics card? The main processor would upload the graphics resources, maybe procedures and graphics commands to the processor and leave it to do all the work. That would be an extremely modern design with stone age parts, actually.
We need some kind of port for that, working title 'DGP (decelerated graphics port)'. It would not be very fancy, but we also don't need to transfer gigabytes of graphics data all the time. It's more like kilobytes, one millionth of the traffic to a modern graphics card.
So what would be your choice for the job?
1) I have two CDP1854 UARTs, which can be hooked up to the processors quite directly. The downside is that this serial connection will work at a bitrate around 28800 kilobits/sec max.
2) I also have two CDP1851 parallel ports. They are just as easily interfaced to the processors and may fall just short of the data rate we need.
3) Another shared RAM buffer, this time between the two CPUs. Nothing is faster than accessing memory directly. So far, so good. The downside here is that the memory, the busdrivers and the bus connector to the main processor's bus will eat up a lot of precious space on the circuit board.
So, which bitter cup would you drink out? Or do you have a better idea? Quick, I want to have great 3D graphics on a 8 bit computer!
I have lived with several Zen masters - all of them were cats.
His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
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I am no expert but the RAM solution sounds great, if you can find sufficient space [EDIT] space on the board...
"If we don't change direction, we'll end up where we're going"
modified 21-Feb-19 7:56am.
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These are 8 bit processors with the then typical 64k address space. Trying out a simpified version of an address bus extension/ memory paging solution is one of the things I want to try out and debug with this single board computer. The simple version would allow the processor to access 4 Mb, the full version 16 Mb. Replacing one of the regular memory pages with one of these shared buffers is no big deal. The chip select signal of one of the regular RAMs is simply redirected or jumpered to the shared one's priority encoder (part of the traffic light, the mutex)'.
I have lived with several Zen masters - all of them were cats.
His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
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Crayons.
#SupportHeForShe
Government can give you nothing but what it takes from somebody else. A government big enough to give you everything you want is big enough to take everything you've got, including your freedom.-Ezra Taft Benson
You must accept 1 of 2 basic premises: Either we are alone in the universe or we are not alone. Either way, the implications are staggering!-Wernher von Braun
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"The members of African heavy metal band Skinflint are eagerly looking forward to playing their first American dates. Starting Tuesday, Feb. 19, the trio will open for fellow heavy metal rockers Soulfly for seven shows, mostly on the West Coast."
"The band blends traditional themes, tales, and rhythms from Africa with the hard-driving rock typical of Black Sabbath and Iron Maiden — two of their many musical influences.
Nkoloso likes hip-hop, jazz, blues, and traditional African music, in addition to heavy metal. Alessandra currently listens to progressive rock in her free time.
Giuseppe started out as a blues guitarist with a passion for rock."
Kevin
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They are actually pretty good, I liked it even though it isn't sung in English.
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Broadcast aired song as arranged (9)
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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Is it song or zong?
"The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge". Stephen Hawking, 1942- 2018
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No. That's three words, and the wrong number of letters.
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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I was thinking about US/Canada residents... and their English...
Can they zing a zong or it must be the UK way?
"The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge". Stephen Hawking, 1942- 2018
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Am I a colonial? I didn't think so ... 
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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Only in the same way that the Gaza Strip is a "colony" of Israel ... hence the 70's ad parody: "Come home to a real fire - buy a cottage in Wales".
The Marple Leaf[^]
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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I'm not sure Welsh and English are so eager to go separate as we do... If just was possible physically...
"The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge". Stephen Hawking, 1942- 2018
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ORGANISED.
Anagram of
OriginalGriff wrote: aired song
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And you are up tomorrow! 
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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Uh... I got "Organised" too but failed to link that with broadcast... didn't occur to me that broadcast was the anagram indicator and arranged was the definition. Thought it was other way around 
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That was the plan!
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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A word with 9 letters, I got confused as well.
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Nah ... "confused" is only eight letters ...
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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Hi all, can anyone stand in for me today - stuck in garage with car and don't have one ready 
We can’t stop here, this is bat country - Hunter S Thompson RIP
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OK.
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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Done - hope the car gets well soon!
(Mine was in Tuesday - MOT and BIG service - fortunately it sailed through with just an advisory on the front brake pads, so those got swapped at the service as well)
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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Mine is the dreaded SRS light permanently on ( Honda CRV )
We can’t stop here, this is bat country - Hunter S Thompson RIP
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Ah. Loose connection to the airbag ... hopefully.
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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