Mostly. This is neat http://news.com.com/Hobbyist+reconstructs+Apollos+computer/2100- 1003_3-5570963.html?tag=nefd.top and so are some of the links from http://starfish.osfn.org/AGCreplica/ There is some real interesting stuff to read on the instruction set and the inner workings of the CPU and don't forget when this was done. Veronica |
A bit of history
Started by ●February 10, 2005
Reply by ●February 10, 20052005-02-10
Now that is a retro project! I am almost tempted to push everything off my table and stick that thing in a Spartan 3 Starter board with PS/2 input and VGA output. What a great way to spend quality time on engineering! --- In , "veronica_merryfield" <veronica.merryfield@t...> wrote: > > Mostly. This is neat > > http://news.com.com/Hobbyist+reconstructs+Apollos+computer/2100- > 1003_3-5570963.html?tag=nefd.top > > and so are some of the links from http://starfish.osfn.org/AGCreplica/ > > There is some real interesting stuff to read on the instruction set > and the inner workings of the CPU and don't forget when this was done. > > Veronica |
Reply by ●February 11, 20052005-02-11
> Mostly. This is neat > > http://news.com.com/Hobbyist+reconstructs+Apollos+computer/2100- > 1003_3-5570963.html?tag=nefd.top > > and so are some of the links from http://starfish.osfn.org/AGCreplica/ > > There is some real interesting stuff to read on the instruction set > and the inner workings of the CPU and don't forget when this was done. > Wow! That's a really cool project. I've been wondering what goes into a guidance computer. Now I can build my own spacecraft :) Rob |
Reply by ●February 11, 20052005-02-11
thats a very good link and its very intresting to see what goes inside a spacecraft... that too in 1964 good job --- veronica_merryfield <> wrote: > > > Mostly. This is neat http://news.com.com/Hobbyist+reconstructs+Apollos+computer/2100- > 1003_3-5570963.html?tag=nefd.top > > and so are some of the links from > http://starfish.osfn.org/AGCreplica/ > > There is some real interesting stuff to read on the > instruction set > and the inner workings of the CPU and don't forget > when this was done. > > Veronica > > > To post a message, send it to: > > To unsubscribe, send a blank message to: > > Yahoo! Groups Links > __________________________________ |
Reply by ●February 11, 20052005-02-11
There used to be a car advertisment on TV (SAAB or BMW or something) that claimed their car had more computing power than that required to put a man on the moon. Engineers had a bit of a chuckle at that, because it was known that the guidance computer was not much more powerful than a Z80 ;-) Sounds like amazing dedication. John. Rob Finch wrote: > >Wow! That's a really cool project. I've been wondering what goes into >a guidance computer. Now I can build my own spacecraft :) > >Rob > -- http://members.optushome.com.au/jekent |
Reply by ●February 11, 20052005-02-11
The AGC has a truly bizarre architecture - clearly application specific. Because the machine was so limited in memory they actually wrote and interpreter and most application programs were interpreted strictly to save memory. They could use lots of lights - the machine was slow enough to see them flash! The AGC used a 1.024 MHz clock and the fast instructions used 12 clock cycles. Memory cycles were 11.7 uS. The 8080 started out at 2 MHz, fast instructions used 2 clock cycles, memory access was 1 uS (IIRC) and the address space was much larger. --- In , John Kent <jekent@o...> wrote: > There used to be a car advertisment on TV (SAAB or BMW or something) > that claimed their car had more computing power than that required to > put a man on the moon. Engineers had a bit of a chuckle at that, because it > was known that the guidance computer was not much more powerful than a > Z80 ;-) > > Sounds like amazing dedication. > > John. > > Rob Finch wrote: > > > > >Wow! That's a really cool project. I've been wondering what goes into > >a guidance computer. Now I can build my own spacecraft :) > > > >Rob > > > > > > > > -- > http://members.optushome.com.au/jekent |
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Re: A bit of history
Reply by ●February 11, 20052005-02-11
Hi Richard, The 6800 I understand because of one (E) Clock = 1 cycle = 1usec. Anyway ... what are you doing up this time of night ? 6pm in Australia ... not sure what that is in the US, but I bet it's early in the morning :-) John. rtstofer wrote: > >The AGC has a truly bizarre architecture - clearly application >specific. Because the machine was so limited in memory they >actually wrote and interpreter and most application programs were >interpreted strictly to save memory. They could use lots of lights - > the machine was slow enough to see them flash! > >The AGC used a 1.024 MHz clock and the fast instructions used 12 >clock cycles. Memory cycles were 11.7 uS. The 8080 started out at >2 MHz, fast instructions used 2 clock cycles, memory access was 1 uS >(IIRC) and the address space was much larger. > -- http://members.optushome.com.au/jekent |
Reply by ●February 11, 20052005-02-11
> The 8080 started out at 2 MHz, So far so good. Later the 8080A-2 was rated at 2.5 MHz,and the 8080A-1 at 3 MHz. > fast instructions used 2 clock cycles, No. Instructions take between one and five "M cycles", each of which can perform one memory cycle and/or some internal operations. Each M cycle takes between one and five "T states" (clock cycles). The fastest instructions take four clocks, and the slowest (XTHL) takes 18 clocks. > memory access was 1 uS The memory access time is misleading. Memory cycle time is more useful. For a 2 MHz 8080, an instruction fetch cycle takes 4 cycles (2 us), and other memory cycles take at least 3 cycles (1.5 us). Reference: Intel 8080 Microcomputer Systems User's Manual, September 1975, Intel literature part number 98-153C. |
Reply by ●February 11, 20052005-02-11
You are correct, of course. I had misplaced my 8080 Microcomputer Systems User's Manual (Sept 1975). I have since located it - right on top of my "Bit-Slice Microprocessor Design" book. I just have to get organized someday... --- In , "Eric Smith" <eric@b...> wrote: > > The 8080 started out at 2 MHz, > > So far so good. Later the 8080A-2 was rated at 2.5 MHz,and the 8080A-1 > at 3 MHz. > > > fast instructions used 2 clock cycles, > > No. Instructions take between one and five "M cycles", each of which > can perform one memory cycle and/or some internal operations. Each > M cycle takes between one and five "T states" (clock cycles). The > fastest instructions take four clocks, and the slowest (XTHL) takes 18 > clocks. > > > memory access was 1 uS > > The memory access time is misleading. Memory cycle time is more useful. > For a 2 MHz 8080, an instruction fetch cycle takes 4 cycles (2 us), and > other memory cycles take at least 3 cycles (1.5 us). > > Reference: Intel 8080 Microcomputer Systems User's Manual, September 1975, > Intel literature part number 98-153C. |
Reply by ●February 11, 20052005-02-11
John According to the time stamp on my post, it was about 11:21 PM - seems right. Yours was about 11:30 PM - all my time (US PST). Seems I recall calculating for some place in Australia that you were 18 hours ahead. Or, California is 6 hours ahead in time but on the previous day. And then we have to factor in Daylight Savings Time. I remember when I went to work in Singapore the days it took to recover from the 16 hour time shift. It was a lot easier recovering from the 8 hour shift when I returned. Richard --- In , John Kent <jekent@o...> wrote: > Hi Richard, > > The 6800 I understand because of one (E) Clock = 1 cycle = 1usec. > > Anyway ... what are you doing up this time of night ? > 6pm in Australia ... not sure what that is in the US, > but I bet it's early in the morning :-) > > John. > > rtstofer wrote: > > > > >The AGC has a truly bizarre architecture - clearly application > >specific. Because the machine was so limited in memory they > >actually wrote and interpreter and most application programs were > >interpreted strictly to save memory. They could use lots of lights - > > the machine was slow enough to see them flash! > > > >The AGC used a 1.024 MHz clock and the fast instructions used 12 > >clock cycles. Memory cycles were 11.7 uS. The 8080 started out at > >2 MHz, fast instructions used 2 clock cycles, memory access was 1 uS > >(IIRC) and the address space was much larger. > > > > > > > > -- > http://members.optushome.com.au/jekent |