PL6/7 pinouts

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cjm
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PL6/7 pinouts

Post by cjm »

Hi,

Does anyone know where I can find the pinouts for the PL6/7 connectors?

Regards,
Chris
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Re: PL6/7 pinouts

Post by Multiwizard »

cjm wrote:
Wed Mar 17, 2021 8:41 pm
Hi,

Does anyone know where I can find the pinouts for the PL6/7 connectors?

Regards,
Chris
Hi,

will this do?... :D


Greetings, Wim... :-)
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Re: PL6/7 pinouts

Post by cjm »

Great! Thanks!
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Re: PL6/7 pinouts

Post by Prime »

Be careful,

IIRC PL6 and PL7 have the two rows swapped with respect to one another, this has caught me out a couple of times :(

Cheers,

Phill.
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Re: PL6/7 pinouts

Post by roland »

Prime wrote:
Thu Mar 18, 2021 11:43 am
IIRC PL6 and PL7 have the two rows swapped with respect to one another.
That is correct !
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Re: PL6/7 pinouts

Post by cjm »

Prime wrote:
Thu Mar 18, 2021 11:43 am
Be careful,

IIRC PL6 and PL7 have the two rows swapped with respect to one another, this has caught me out a couple of times :(

Cheers,

Phill.
Thanks, useful to know!

Chris
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Re: PL6/7 pinouts

Post by bprosman »

Prime wrote:
Thu Mar 18, 2021 11:43 am
Be careful,

IIRC PL6 and PL7 have the two rows swapped with respect to one another, this has caught me out a couple of times :(

Cheers,

Phill.
Well ... sort of, but with a reason. The internal PL6 is designed to connect a board via a "straight" connector while the external connecter is designed for an angled DIN connector. So for the extension board it doesn't make any difference.
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Re: PL6/7 pinouts

Post by roland »

But still then you'll have to pay attention how to mount your connector: the 64 pin connector on the FDC board is located at the solder side :!:
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Re: PL6/7 pinouts

Post by cjm »

Why is the Atom's PCB upside down? :roll: It really doesn't help that in order to compare the two connectors you have to flip the board over and rotate it :? :lol:

Anyway, this is what I think the pinouts look like...
PL7.png
PL6 (2).png
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Re: PL6/7 pinouts

Post by Louis.m »

Hello 10 all,

There is an Atom-life-threatening Dangerous Error in the photos/images of the PL6 and PL7 in this this thread !
In both cases the indication of rows A and B are contradicting manufacturers specifications.

I checked the copper-lines on a 202,000 Issue 5 Atom PCB and these were coherent with my suspicions.
This leads to the awkward conclusion that the data in the images posted here are dangerously wrong.

Unfortunately, I only discovered this after I had killed my own precious 8271 . . . 😭 ❗
Now I am searching for a replacing 8271 FDC, does anyone have a spare IC for me, pretty please with sugar on top 🙏 ❓

A simple rule of thumb to remember what is the right way around (the rows of copper soldering holes, from the edge of the PCB downwards): Think of the name of a Swedish pop group ABBA !

Hoping to prevent others from making the mistake I did !

Gr😥😥tings, Louis.m
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Re: PL6/7 pinouts

Post by cjm »

Louis.m wrote:
Thu Sep 23, 2021 7:50 am
There is an Atom-life-threatening Dangerous Error in the photos/images of the PL6 and PL7 in this this thread !
In both cases the indication of rows A and B are contradicting manufacturers specifications.
I think the diagrams are correct. So it is BAAB (and not ABBA).

5v should be present on pin 1a. Can you double check with a meter?

Chris
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Re: PL6/7 pinouts

Post by danielj »

I think the thing I would take from this is *always* double check positions of important pins (i.e. power etc) with a multimeter before you plug anything in, as CJM said. I'm so used to people doing diagrams the opposite way around to the way I'd think about things I just do this by default.
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Re: PL6/7 pinouts

Post by danielj »

I just buzzed it out on my atom - the labels are right so far as I can tell?

d.
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Re: PL6/7 pinouts

Post by hoglet »

danielj wrote:
Thu Sep 23, 2021 10:16 pm
I just buzzed it out on my atom - the labels are right so far as I can tell?
The labels and numbers are correct as far as I can see as wll.

I think the possible confusion is only over which is row A vs row B.

(and it also doesn't help that Acorn missed the A vs B bit off the Atom schematics)

Looking back at the System schematics, the important 6502 bus signals are all on "Side A". But it's not clear to me whether what Acorn calls "Side A" is the same as what the DIN41612 people call "Row A".

But it gets worse....

It's also possible this has changed between the System and the Atom. I managed to convince myself this morning that the Atom RnW signal is on pin 30 of the inner row of PL6 (away from the PCB edge, which is row B in DIN41612 speak). But on the System One it's on pin 30 of the outer row (neaest the PCB edge, which is row B in DIN DIN41612 speak). This really surprised me, so I'm probably wrong.

I was looking at the System One PCB photos here:
http://speleotrove.com/acorn/acornPictures.html

Dave
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Re: PL6/7 pinouts

Post by hoglet »

I'm still pondering this....

I'm fairly convinced now the A/B designation on Chris's diagram for PL7 (the internal connector) is correct.

But I'm still confused about PL6 (the external connector), where the rows A/B rows seem reversed from the normal Acorn system convention.

Looking at pictures of the Acorn Atom DIsk Pack FDC card, it seems they soldered the connector onto the reverse of the PCB, which has the effect of reversing rows A and B:
https://commons.wikimedia.org/wiki/File ... Hi_Res.jpg

There are more pictures of the disk pack here:
http://chrisacorns.computinghistory.org ... cPack.html

I wonder if this was deliberate, or whether Acorn actually made a mistake on the Atom.

See also this thread: PL6 & PL7 where Phil struggles to connect a Acorn System VDU Card to PL6.

Dave
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Re: PL6/7 pinouts

Post by roland »

One of our club members used the following trick on his memory board: instead of two rows he placed four rows and connected them. This way it's possible to connect the board inside or outside the Atom.

Screenshot 2021-09-24 at 10-16-50 Atom Nieuws – Acorn Atom.png

It might be necessary to cut a slice of the pcb edge to make a 2x32 connector fit.

When I design a board for the Atom PL6/7 I always think ahead whether it will be internal or external and triple check the signals before connecting the board.
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Re: PL6/7 pinouts

Post by Louis.m »

Hello 10 all,
roland wrote:
Fri Sep 24, 2021 9:21 am
One of our club members used the following trick on his memory board: instead of two rows he placed four rows and connected them. This way it's possible to connect the board inside or outside the Atom.
These double connector rows (if its on an original Acorn FDC board) are, similar to the ones inside the Atom and with same connector types, meant to stack other boards on top of the FDC board inside the disk drive enclosure !

Greetings, Louis
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Re: PL6/7 pinouts

Post by Louis.m »

Hello 10 all,

Here is my (final ?) plea in this case.

First, let's assume I'm not completely insane (only a byte Six Five O Two).
Second, I already double checked before publishing my first comment here.
Third, after more than forty years of working with electronics, I have some experience in the matter.

Remark, despite the above I was stupid enough to follow information without checking before use (this caused me frying much of an 8271 FDC board :-( ) !

For all sake I have triple checked some connections of PL6/7 before this publication.

Now, let's begin with a look at some officially recognized manufacturers data (I only show one page, but data from all manufacturers are similar).
Page 22.png
Here we can see that on the angled male connector the pins in the wide gap are row A and in the smaller gap row B (both with pin 1 at the right).

Next the actual Atom situation.
PL6.png
Here we see PL6 in the same position.

Measurements tell that pin B1 is connected to +5V (I'll come to pin A1 later), further measurement tells pin A3 is connected to PB7 (pin 17 of IC1, the 6522 VIA, see drawing at bottom of this writing). All other measurements are corresponding.

Next picture shows the solder side of an Atom mainboard (202,000 Issue 5).
Solder side Top right.png
According to the data from the manufacturer the top row here is . . . A the second row must be B, keep in mind the top row here is the bottom row in the previous image, because the connector is at 90° to the PCB and the whole is turned over an other 90°!

Interlude, about pin A1.
If we zoom in on the left of the connector rows we see that all four pins 32 are connected, these are the ones carrying GND.

Zoom in on the right and we see only the second and third row are connected (carrying +5V), the first and fourth row are not connected to anything, measurement tells that, concerning PL6 A1 and PL7 A1, here is no connection to whatsoever on the component side either, not even between pins A1 on row 1 and row 4 on the PCB.

Furthermore we see that on the whole all pins except A1 are connected in pairs, row 1 (top) to row 4 and row 2 to row 3.

Back to the main theme of ABBA now, so row 1 (Yes, the one Close To The Edge of the PCB) is row A and row 2 is row B of the male connector, there off we can only conclude the order must be ABBA !

PL7.jpg
The above picture (PCB component side) tells the rest of the story, here is PL7 with the wide row A (now on top, because the PCB is again turned over, this time 180°) and row B closer to PL6.

Des Pudels Kern, the (h)art of the matter, is that in the original drawing by Acorn, no row A or B asignment is shown, this caused al the confusion over the years (with as one of the latest results me frying a 8271).


To be sure to be sure, we'll have a look at things sideways, picture by picture, turning each picture left to back and right to front.

Picture 1, the page with manufacturers data, in the top part of the drawing, row B (smaller gap) is the top one.

Picture 2, row B still on top.

Picture 3, the connections make a 90° turn clockwise behind the male connector and the board is also turned 90° clockwise, therefore row B is now the second one from the top.

Picture 4, here the board is turned 180° (CW or CCW doesn't matter), row A of the male connector (Close to the Edge) is now the bottom one, this row 1 is connected to row 4 (remember picture 3).

Again ABBA !


Last but not least, here a copy of the original drawing with assignment of rows A and B added.
Part of  Drawing with A&B assigned.png

Hopefully this will help preventing future catastrophes like the one that happened to me.


Greetings as ever, Louis

P.s. to everyone who likes to think otherwise: We live in a free world (but don't blame me for the result).
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Re: PL6/7 pinouts

Post by oss003 »

In the Hobbit schematic, the A and B rows are marked.

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Re: PL6/7 pinouts

Post by hoglet »

oss003 wrote:
Fri Sep 24, 2021 6:19 pm
In the Hobbit schematic, the A and B rows are marked.
Is there a higher res version of that? I can't read it properly.
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Re: PL6/7 pinouts

Post by Louis.m »

oss003 wrote:
Fri Sep 24, 2021 6:19 pm
In the Hobbit schematic, the A and B rows are marked.
Hallo Kees,

Tsja . . . !

Unfortunately your picture is too vague to be readable.

Luckily I also have a copy of that Hobbit in my own collection, so I climbed the ladder (my library is 3m60 high), grabbed the Hobbit by the tail and sure enough, here it was. Unfortunately also the wrong info, the editors probably fell into the same trap as many of us did !

As I wrote before, Acorn has never released an official diagram with A&B designation (as far as I know).

The question now becomes, which is predominant, the claims made in a hobby magazine, or the DIN standard (which is used worldwide by many a professional manufacturer) that was prescribed by the "Deutsches Institut für Normung" at the time the first DIN 41612 connector was manufactured (before the Acorn Atom even existed) ?

I think we "Atomists" were mistaking all the time, a misleading caused by (1) the fact that Acorn has dropped a stitch by not designating A and B in the original drawing, (2) the fact that in "those days" industrial data wasn't as readily available as is now, and (3) publications in a Hobb(y so be )it magazine.

But is a mistake no longer a mistake when it becomes a Hobbit habit ?

By the way, I learned to distrust any of the publications other than those of the industry (and even those), since I read an introduction of CMOS logic (mid last century or so) in which was mentioned that, because of higher vulnerability to distortion than the until than common TTL logic, all unused CMOS inputs and outputs had to be connected to GND !

Unfortunately I have not been professionally active for a while, and by experimenting to build a new Atom, I have now dropped a stitch myself by running into a decennia old trap, resulting in a fried FDC board (a lesson learned twice is a lesson learned well :oops: ).

"Een ezel in't gemeen stoot zich geen twee maal aan d'zelfde steen.", ik wel dus ben ik geen ezel maar eerder een gewoon rund =D> !
For the undutched: "A donkey (ass) in general doesn't hit the same stone twice." #-o, I did, so I'm not an ass but a mere ordinary ox :mrgreen: !

Gr :D :D tings, Louis
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Re: PL6/7 pinouts

Post by cjm »

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Re: PL6/7 pinouts

Post by Multiwizard »

cjm wrote:
Fri Sep 24, 2021 10:35 pm
Hi-res version here: https://archive.org/details/CoverFB/17-05-1980Left.png
I wonder who uploaded that one?... :mrgreen:
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Re: PL6/7 pinouts

Post by Louis.m »

Hello Chris,
cjm wrote:
Thu Sep 23, 2021 7:51 pm
I think the diagrams are correct. So it is BAAB (and not ABBA).

5v should be present on pin 1a. Can you double check with a meter?

My points are as follows:

  • The internationally recognised DIN standard for these connectors is older than the Acorn Atom, and certainly older than the Hob-bit article.
  • According to the DIN norm the lower row in the connector (closest to the board) is A.
  • The connections of PL6 are bend 90° behind the connector but don't cross each other, therefore the row on the PCB closest to the edge must also be A.

Please correct me if I'm wrong !

Concerning the 5V at pins A1 and B1, read my contribution to this topic and view the images I published
(I think it also proofs without any doubt it's ABBA).

Gr :D :D tings, Louis
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Re: PL6/7 pinouts

Post by dominicbeesley »

I'm coming to this a bit late but I've been designing a board for the System series and wanted it to work on an Atom (I already had a board that looks to be designed for the Atom's external/flipped connector here:viewtopic.php?p=337217#p337217

A couple of points I'd like to sanity check before continuing

1. external connector is flipped
I'm fairly convinced that the internal connector is the right way round with regards to rows A and B. It is the external one that is 'wrong'. The internal connector matches the System pinouts as far as I can tell

2. Flipping the 90 degree connector to the other side of the pcb DOES NOT remedy things
Flipping sides will reverse the pin numbering not the rows. To flip rows and keep correct numbering one would have to flip sides *and* rotate through 180 degrees? ( the connector would then be pointing inside the case)

I'd be grateful for a confirmation of the two points above. If this is the case I think the best option might be a converter board with back to back connectors and a small pcb to swap the rows over. Would there be any interest in such a thing? Or maybe even a mini backplane with a few slots?

D
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Re: PL6/7 pinouts

Post by Louis.m »

Hi Dominic,

Please, study my contribution to this thread: viewtopic.php?p=335745#p335745 , I think it will answer your questions.

For the sake of completeness, I have to mention that the outer connector (PL6) can only be placed the way it is and (as far as I know) a mirrored version of such connector, with row B closest to the PCB side, is never been used (not even produced ?!).

On the other hand, the inner connector (PL7) can be placed in two ways, but the way with the notch towards PL6 (as in the 4th picture) is the right way (the other way around PL7 row A will be connected with PL6 row B), a simple measurement for conductivity between pins of both connectors will confirm this !
See: download/file.php?id=74882&mode=view, the 4th picture in my reply (the one that also shows the VIA IC).

Gr :D :D tings, Louis
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Re: PL6/7 pinouts

Post by hoglet »

dominicbeesley wrote:
Sat Oct 09, 2021 10:41 pm
1. external connector is flipped

I'm fairly convinced that the internal connector is the right way round with regards to rows A and B. It is the external one that is 'wrong'. The internal connector matches the System pinouts as far as I can tell
Agreed.
dominicbeesley wrote:
Sat Oct 09, 2021 10:41 pm
2. Flipping the 90 degree connector to the other side of the pcb DOES NOT remedy things
Flipping sides will reverse the pin numbering not the rows. To flip rows and keep correct numbering one would have to flip sides *and* rotate through 180 degrees? ( the connector would then be pointing inside the case)
Agreed.

Dave
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Re: PL6/7 pinouts

Post by hoglet »

Louis.m wrote:
Sat Oct 09, 2021 11:48 pm
On the other hand, the inner connector (PL7) can be placed in two ways, but the way with the notch towards PL6 (as in the 4th picture) is the right way (the other way around PL7 row A will be connected with PL6 row B), a simple measurement for conductivity between pins of both connectors will confirm this !
I'm still not convinced your logic is correct here...

Surely Row A of PL7 is the row nearest the edge of the PCB, regardles of how it's connected to PL6,

My current view is that PL7 is wired the same as it is on the System, only PL6 is reversed.

Dave
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Re: PL6/7 pinouts

Post by Louis.m »

hoglet wrote:
Sun Oct 10, 2021 1:33 am

I'm still not convinced your logic is correct here...

Surely Row A of PL7 is the row nearest the edge of the PCB, regardles of how it's connected to PL6,

My current view is that PL7 is wired the same as it is on the System, only PL6 is reversed.

Dave
Hello Hoglet,

Just have a good look at the manufacturer specifications (DIN norm): download/file.php?id=74879&mode=view
Then look at my other pictures made of an original Acorn manufactured Atom (no self build kit !), what do they tell ?
Of both, PL6 and PL7, the two (by DIN as such specified) B rows are adjacent and electrically connected by the PCB, if this does not convince, what will ?

PL6 the wrong way ? It is possible to mount PL7 the wrong way, but it is physically impossible to mount PL6 wrong, if tried so, PL6 points inwards and won't fit because of PL7 needs that space !

Gr :D :D tings, Louis
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Re: PL6/7 pinouts

Post by lovebug »

It was a long time ago but I remember having an acorn atom schematic that had the edge connector A and B incorrectly labeled in reverse

I do remeber looking at the pcb pads and the row closest to the pcb edge is row A and behind that is row B, pin 1B is +5v if that helps ?

I never used the internal connector
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