Mysterious SYNC in Apple-1 Manual / Diagnostic card for Apple-1

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speedyG's picture
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Hello to all AFmembers,
while waiting for the CFFA1 to arrive ( i want to test the expansioncards in all possible configurations
with the CFFA1 too, to ensure that no interactions interfere with the CFFA1 )....

In the meantime I started to make a kind of simple disgnostic card on one of the prototypecards consisting
of the adressdisplay with LEDs and a "single step" switching logic as described in the apple-1 manual at page 12.

In that circuitplans there is a signal used, labeled as SYNC. In fact i have searched the remaining plans
at page 14 and 15 and i haven´t found that signal there anywhere.... it´s also not labeled at the apple-1 slot !

Here the prototyp card with the chips numbered according to the page 12 parts shown below too:

here the plan for display of the adressinglines with LEDs:

and here the part that displays the single step logic:

another problem is that the signalnames labeled to the 7474 don´t match with the pin names displayed in the
datasheet.

At the moment i am trying this by a kind of "best guess".....

if anybody has idea about the correct pinouts of the "single-step plan" corresponding to the datasheet
or
any idea where to locate / or what signal from slot is to be used as "SYNC"

any kind of feedback here would be welcome....

sincerely speedyG

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Clint's picture
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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card doe ...

Sync is pin 7 on the 6502.

As for the 7474; I think this pinout will make things clearer for you:

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speedyG's picture
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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card doe ...

Hello Clint,
thanks a lot... this realy brings me ahead.....
just one question: which source did you use to get the pinouts shown above ?

I just pulled out datasheet from my archive and it just displayed the signals on the outside of the drawing....
the signals inside the border i tried to figure out by the signals which are clear:
S1, D2, Clk1, CLK2, Q1, Q2, Q1´, Q2´. GND and Vcc.
The Pins 1,4, 10 and 13 are displayed to be inverting or active low inputs... so from datasheet i was forced to make a guess....

sincerely speedyG

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In early days I had a lot of money but no time - now I have no money but a lot of time....
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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card doe ...

Synch is BA, labeled as BA/Synch on the 6502 on the schematic.

Clint's picture
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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card doe ...

The information you needed on the 7474 is on the TI Datasheet under the heading 'logig symbol'

here is a snip:

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speedyG's picture
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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card doe ...

Hello to all AFmembers,

thanks a lot again for this informations.
It seems to me that i should prefer the datasheets from TI....
most of my datasheets have origin from NS and they don´t have that labeling....
this correction possibly prevented some harm ......
in the meantime i corrected the three wires...

sincerely speedyG

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dsm
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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card for ...

29Jun13

SpeedyG,

I really like the idea of a bus diagnostic card for Apple1 variants which allows halting, single-stepping, etc.
I have a couple comments that you might find to be useful.

  • It would be useful to display the data bus in addition to the address bus.
  • It would be useful to display the control signals in addition to the address bus.
  • The photograph of your prototype shows SN74ALS174N parts. My recollection is that 74ALS devices source (Ioh)(0.4mA) much less current than they sink (Iol)(8mA). Since your LED common is tied to GND, a HIGH may turn on your LEDs, but not very brightly. One alternative would be to use an octal inverting register like the SN74ALS534A and tie your LED common to VCC. Another alternative would be to use an octal register with symmetric drive capabilities like the SN74HCT374 or SN74HCT574 and tie your LED common to GND.
  • Another, albeit expensive, option would be to use a hexadecimal LED display like the HP 5082-7340 that contains driver circuitry (including a latch). I tend to think providing both binary and hexadecimal displays would be a good idea.
  • The design may be somewhat complicated by the slight differences in hardware behavior between the NMOS and CMOS implementations of the 6502.

Thanks for your time.

Cheers,

dsm

speedyG's picture
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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card for ...

Hello dsm,

well to tell the truth i allready thought about it, but at the moment i just wanted a card to make fast
diagnostics while starting up the replicaes to see if the adressbus is running along path while startup.
I didn´t have enough more LEDbars to realize - at the moment i made that card....
besides i used the card for taking signalmeasurements from the two rows above the slotconnectionpadsto my oscilloscope.... maybe when i have finished the shipping of the 4 expansioncards i might make one with all
signals and real routing as own card....

in that case your tips would turn out to get valuable hint....
at the other hand i also just wanted to show how the prototype card could just be used....
anyhow thanks for the feedback ....
sincerely speedyG

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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card for ...

That would be cool. A front panel like the IMSAI, possibly minus all the toggle switches.

Just think of the cool patterns that could be displayed on the LEDs with timing loops etc Wink, no to mention some serious debugging.

Reminds me of a trick someone showed me in the late 70's We had a Data General mini computer, by loading various programs (from paper tape) we could generate music by various timing loops (in pure assembler) and putting an AM radio in close proximity to the CPU. The leaked RF was very clear and distinct. In addition the Data General Nova's had address and data lamps so the lights flashed in time with the music.

A blast from the past.

Cheers, Martin..

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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card for ...

In case anyone's interested, here is info on the AppleThrottle - a card for the Apple II that used game paddles to control the speed of the CPU. It was quite fun to slow down the processor so that you could watch how the screen scrolled text for example. I also built an AppleThrottle II that used an address decoder to trigger the delay. With the help of the ROM listing, this could be used in various ways to scroll one line at a time for example.

Also attached is an article from SofTalk magazine that I wrote on the ATH-1 and the John Bell display board.

ATH-1 info

speedyG's picture
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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card for ...

Hello to all AF-members,

after several short sessions with the card displayed above, i do agee with
the member dsm and with mnc1959....
displaying only the adressinglines - like proposed in the Apple-1 manual isn´t that usefull....

for "hardcore"-diagnostic it´s rather more recommended to also see the databuslines and the clockingsignals
as well as the availiable "controling"-lines including the lines that control
the interfacecards ( R, S and T ).

Therefor i have made a new card including all signallines at the slot
- in connection with the additionaly proposed chance of using singlestep-mode for debugging and
- just because it´s also useful adding a Reset-button and a button to trigger the NMI.

Both should be availiable, because
- after a Reset also the Basic or program in memory is "blown away"

- while the NMI offers the opportunity to keep that stuff still in memory and
turn back to a crashed program ( which turns out to be usefull if you end up in an "eternal" neverending loop ).

I start with the altered circuitplan and then i took a picture after each stage of the
wiring.... i also used different colors of wires to make different signalbusses better viewable.

so here is the circuitplan:

here i made the powerlines to the sockets:

here i added the datalines D0 to D7 to the one socket:

here is added the adressing-lines to the next 2 sockets:

here i started adding resistors to the Anode-lines of the LED-bars:

here i added the "control"-lines to the forth socket:

next i added the clocking lines to the fifth socket:

here is again adding of the resistors to the Anode-lines of the LED-bars:

and here a picture for better view to details :

here i added the labels to the LED-bars indicating the displayed signals:

here i added the wires to pulldown the OE-lines ( Output Enable ) to "LOW" for permanent action:

here i added the wiring to the last socket and the switches for the stepping logic:

and here is a view to the top of the card showing the LED-bars that indicate the signals labeled at the side:

and here a final view to the top of the card with view to the LED-bars and the related labels:

i hope this encourages more members to also make documentation about their own projects -
even if they are aimple and to make pictures and publish here a posting talking about the experiences
they have made while making their project..... sharing their knowledge and thereby offering others to
make benefit from their experience....

enjoy the pictures and rebuild it, if you have interest... viewing the steps you might realize that such
a card is less difficult, than it looks alike - when just viewing the final result --- watching the development
in single steps, you will realize : it isn´t that hard.... just carefull solid work of one day and slow
but carefull soldering-job ( of course it´s recommended to use good tools to get good results... )....

sincerely speedyG

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In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....

speedyG's picture
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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card for ...

adding some pictures....

here a picture of the rearside and the added LE-lines that enable the latching of the LED-bars:

here a view to the topside and in detail the added switch that controls the LE-lines:

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In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....

speedyG's picture
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Re: Mysterious SYNC in Apple-1 Manual / Diagnostic card for ...

Hello AF-members,

in the final step- i removed unused areas of the card at the side heading
to the powerconnector and the cooling sink of the MIMEO/NewtonNTI ....

and here is the Apple-1 Diagnostic Card in use:

sincerely speedyG

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In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....