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Old 12th May 2020, 11:12 pm   #81
philoupat83
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Default Re: Good review of SC/MP.

plan to correct
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Old 13th May 2020, 1:20 am   #82
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Default Re: Good review of SC/MP.

Quote:
Originally Posted by Timbucus View Post
I do not think any other provision is needed to use the 600 then - this would be easier for other builders as well.
I think you may need to tie NENIN to 0v rather than +5v for the SC/MP 2.
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Old 13th May 2020, 8:12 am   #83
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Default Re: Good review of SC/MP.

slothie yes for ENIN see article elektor December 1977 page 12.11
and 12.10
yes for replacement on the model
I finalize the plan
R11 R8 remains cloudy?
BREQ =NBREQ to GND pin 5
ENIN=NENIN to GND Pin 3
VSS =GND pin 20
VGG=VCC pin 40
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Old 13th May 2020, 8:58 am   #84
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Default Re: Good review of SC/MP.

You are correct guys thanks ENIN will need to be changed as well to GND not 5V but, I think that NBREQ must still be tied to Vcc as the description says it must be tied by a load resister to Vcc in the data sheet - hence why the same wiring works when changed to patch +5 to -7 (it effectively inverts it from the SC/MP I/500 anyway)

I am certain of the arrangement of R11 it ties the center of the RUN/HALT three position switch to +Ve - that then either connects to the top pin which is hooked to D7 so that when DOWN it halts on a '00 Breakpoint instruction (as the center pullup on R11 is connected to the D7 line and onto Pin 2 of IC2), when UP it grounds Pin 2 of IC2 through R11 leaving a Low all the time on Pin 2. In the CENTER the pullup keeps Pin 2 at High. This means that NADS (inverted by Pins 12/13 of IC2 out to Pin 11 onto Pin 1) controls the Halting in conjunction with a breakpoint, Never (free run) or Halting each cycle.
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Old 13th May 2020, 9:21 am   #85
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Default Re: Good review of SC/MP.

On your "plan to correct" nice routing to avoid the links but, I still think your reset arrangement is wrong again the switch should reset when depressed I think which needs the ground at the top - take another look at my diagram posted earlier - this also illustrates I do not yet get R8 and the Slow / Step arrangement. I also think R3 and R4 are labelled the other way I have changed my annotated schematic to reflect that as well.

(EDIT: I just looked, you have done the same with the data switches - remember DOWN shorts the Center pin to the top/right side in your diagram - as I said in an earlier post the 1 position is UP which means the ground has to be the center connection and the Data the top/right side in your diagram. This is easily fixed just draw the 8 dots below the ground wire and rub out the other ones...

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Snap on the diagram by the way I was trying to work out the route for the flags etc last night and drew one (they will need a compare I did not like that I had to squeeze A6 and A5 between two pins - that might not track).

(EDIT: Thank you Philoupat83 - my mistake was continuing the data lines - that does not need to happen on the RAM!! - I did not do that on my built one so I can only think I was tired... it is a shame my memory will not be here until next Monday now when I am back in work so I cannot try my machine, maybe I can make an adapter for my AM9111 chips from the MK14... )

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I think it will be worth adding a small header in those lines to allow the option to take them to the Buffers and the LED's or tap them off for projects like a tape or serial interface - on a PCB layout this can continue into the 8 data ports as well. This will allow using jumper wires to connect to the I/O chips rather than having to hard wire them if we put two four pin headers by them as well - I show the Flag and Serial one on the above.

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Old 13th May 2020, 10:27 am   #86
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Default Re: Good review of SC/MP.

or 7407 drivers is the right choice see datasheet R11 seems to me pullup rst for avoided a false contact and an untimely reset R8 is the pullup of R/H
for switches it is necessary to define a convention
UP action contacts at the bottom
ex: rst up multisim me confirmation gnd raz
slow up
step up a pulse
r/h up r/w pitch
load up nds
remains his SB?
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Old 13th May 2020, 10:35 am   #87
Slothie
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Default Re: Good review of SC/MP.

There's some excellent work going on here lads, really enjoying reading this.
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Old 13th May 2020, 11:03 am   #88
Timbucus
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Default Re: Good review of SC/MP.

Glad you are enjoying the diversion Slothie while we await the PCB's from Sirius! Glad to see you are recovering and active here again - your observations and contributions to this rebuild as always are most welcome...

As regards the convention of the switch I am taking my lead from the SunMoonStars photograph that shows the '1' as being UP and the '0' (when grounded) as DOWN.

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This also gives the clue that the HALT position is DOWN (i.e. D7 hooked to R11 bottom by using the TOP pin on the SW) and RUN is UP (R11 bottom to GND shorting the the BOTTOM pin on the SW).

My original notes did not mention this as the source so I had to re-read the review and the Register article as I knew I had seen it mentioned somewhere - then I remembered.

Pressing DOWN for RESET, STEP and LOAD just seems a natural action when you hold the physical board. In any case they should all be in the same direction. That is the way I have built them on my machine and it does feel 'right'.
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Old 13th May 2020, 11:09 am   #89
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Default Re: Good review of SC/MP.

It is a shame we cannot get the admin to rename the thread to have (rebuilding the BYWOOD SCRUMPI) at the end so people browsing or searching will be able to find the topic in the future.

I am also struggling still with the address routing on the RAM chips - I cannot make it work without having two route between a single pair of pins and I cannot see where I differ to phil... who does not seem to have that problem.

One point is that I think A6 needs to be above the GND on IC7 so that the top six lines end on that chip correctly.
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Old 13th May 2020, 11:24 am   #90
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Default Re: Good review of SC/MP.

Just so you can see my problem here is the detail so far...

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Old 13th May 2020, 12:31 pm   #91
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Default Re: Good review of SC/MP.

OK I think I have it now - it was moving the CE up one further to emerge between pins 2 and 3!
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Old 13th May 2020, 12:55 pm   #92
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Default Re: Good review of SC/MP.

A 2112->2111 adaptor is pretty easy - although the 2112 is 16 pin and the 2111 18 pin, the extra pins are on one end of the chip so you just need to connect:
Code:
2112. 2111
----  ----
1-8.  1-8
9-16. 11-18
NRDS  9
8.    10
Note Gnd (pin 8) also connected to second chip enable on 211 (pin 10)
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Old 13th May 2020, 1:48 pm   #93
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Default Re: Recreating the Bywood Scrumpi

Quote:
Originally Posted by Timbucus View Post
It is a shame we cannot get the admin to rename the thread to have (rebuilding the BYWOOD SCRUMPI) at the end so people browsing or searching will be able to find the topic in the future.
Title updated
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Old 13th May 2020, 3:07 pm   #94
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Default Re: Recreating the Bywood Scrumpi

Thank you AC/HL!
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Old 13th May 2020, 3:21 pm   #95
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Default Re: Recreating the Bywood Scrumpi

yes I valid but the datasheet of isp 8A gives normal reset at 1 raz when 0
r/h I think run up halt with d7
low active active prot high
load à gnd bas load data haut
I added the straps for an ins 8060
thought that the switches act backwards
high low circuite
low circuite high
two plan has corrected
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Old 13th May 2020, 3:21 pm   #96
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Default Re: Recreating the Bywood Scrumpi

our little recreation seems interesting it’s great
remains the pcb I reflect to the problem of the straps on eagle and the routing in manual a first
I found out how to do the serigraphy in white but can be slothie and it ok to create the pcb
I would make a complete plan to eagle
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Old 13th May 2020, 3:32 pm   #97
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Default Re: Recreating the Bywood Scrumpi

I think you’re right all my switches are upside down the action is down and not up I correct this error (let’s not forget that scrumpi is English)
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Old 13th May 2020, 3:51 pm   #98
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Default Re: Recreating the Bywood Scrumpi

correction
to check and corrected if error
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Old 13th May 2020, 5:20 pm   #99
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Default Re: Recreating the Bywood Scrumpi

Looking good I was working in that I/O area as well. I have had to update my annotated circuit diagram diagram to reflect the actual pins used for the straps as from the black and white photo. You can see that RAM CE comes from PIN 8 and A11 goes to PIN 12. Sorry if you used that to draw the diagram. Here are the corrections (in Red) note there is an error on the wiring on the Protect switch I have yet to redraw the actual . I may change my vero wiring to be the same if I have time:

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I may have a different data sheet to you for the 74C173 as you seem to have different pins. I am still working out how to set them as Input or Output (seem to tie 1&2 and 8&9 to something), where to connect the CE for I/O (just have a PAD at the moment) and what to do with the Reset PIN 15!

So at the moment my plan detail is below - thanks to you for the Power routing. Note that I have put NWDS feed between a pin lower than you as I am sure 1&2 will need to be joined somehow, it may even need to go lower once I work out how to use that chip.

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I have managed to find space on my Veroboard for one of them so I can experiment when it runs.

Thanks to Slothie I may well make up a RAM adapter and try it out in the next evening or two!
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Old 13th May 2020, 8:08 pm   #100
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Default Re: Recreating the Bywood Scrumpi

I'm a bit confused about the wiring around the protect/load switch. Is the change you have made on the diagram a deliberate choice or just how you have it at the moment? I can't see what the change is intended to do. On the original PROTECT prevents anything from changing the ram; on the last diagram the cpu can stilll write to ram.
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