A new generation of PLA for the C64 is now available.

Disk drives, Monitors, SuperCPU etc.
User avatar
eslapion
Member
Member
Posts: 607
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: A new generation of PLA for the C64 is now available.

Post by eslapion » Wed May 24, 2017 5:20 am

@janilaa
One interesting detail just occurred to me.

You indicated you measured the response speed of PLAnkton as 10ns on all lines except CASRAM on which you get 35ns. However you took these measurements with a 200 MS/s or 5ns per sample.

Our target device was the 8700 rev. 2 which has 16 ns response speed on all lines except CASRAM on which it has 24ns, as measured with a 500 MS/s logic analyser or 2ns per sample. However, to improve compatibility on boards 326298, KU-14194 and 250407 rev. A which don't have an RC filter on CASRAM, we had to increase CASRAM latency to a target of 38ns which is the same as what you get on the early 82S100. In fact, early PLAnktons' RC filter components have exactly the same values as those found on actual C64 boards; 82 Ohms and 150pf.

I checked that the 8700 rev. 2 will work fine on board 326298 IF the RC filter Commodore implemented on boards 250425 and later is added.

The present revision of PLAnkton has been measured as having a response speed of 14ns on all outputs except CASRAM which has a response speed of 38ns as verified with a 500MS/s logic analyser. Both of these are just a bit faster than where the next sample would occur with a 200 MS/s analyser.


Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

janilaa
Member
Member
Posts: 17
Joined: Fri May 19, 2017 10:37 am

Re: A new generation of PLA for the C64 is now available.

Post by janilaa » Wed May 24, 2017 9:38 am

I've been trying to find a MOS PLA that is that fast (16ns), but haven't found one yet. I opened some more (about 30) of my C64's, but didn't find one yet.
All 906114's I found and measured showed about 25ns on other outputs than #CASRAM. I did find one PLA that had 8700-001 marking on top of it and that had the same 25ns also. The 906114's I measured were manufactured in different countries, in different years and had some differences on the markings on top and even the package thickness had variations, but they all had similar timing results. I was measuring 906114's that had dates 86 or later, trying to find a 16ns version...

I did however re-measure Fujitsu-made 251064-01 (found in one my my SX-64's) and it did show about 15ns delay on all outputs, including #CASRAM.
I had somehow missed that this PLA was that fast. I now have written down the PLA type of about 50 of my C64's and SX-64's and have just found one 251064-01, so they are pretty rare and I was concentrating on the more popular versions.

I have PLA's labeled as 82S100(couple versions), 93459PC(couple versions), PLS100, 251064-01, 8700-001 and 906114-01(many versions).
I may find more variations as I have still lot of machines to check...

I haven't found a CSG-labeled late 906114-01 yet, is this the one with 16ns/38ns timing?
If someone has a CSG-labeled PLA for sale, I'd be interested in buying one!

Most of my C64's are PAL-versions, maybe there is the difference...?
I'm also hoping to get more accurate results when I get a new logic analyzer (just ordered one with 500MS/s sample rate) , but it sounds strange if these measurements are off that much. Not saying it wouldn't be possible though. Also my measurements seem to match skoe's measurements on PLA Dissected, but then again he was using 200 MS/s logic analyzer like I did.

Anyway, timing PLA like you have done is perfectly fine and Commodore did that too (at least in 251064-01), I just chose different timing based on my findings.

User avatar
eslapion
Member
Member
Posts: 607
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: A new generation of PLA for the C64 is now available.

Post by eslapion » Wed May 24, 2017 1:41 pm

janilaa wrote:
Wed May 24, 2017 9:38 am
I did however re-measure Fujitsu-made 251064-01 (found in one my my SX-64's) and it did show about 15ns delay on all outputs, including #CASRAM.
I was going to say the 251064-01 is what you should look for. Some have 15-16ns on all outputs and some have 16/24ns. These can only work properly on C64 equipped with C204/R42 RC filter.
I haven't found a CSG-labeled late 906114-01 yet, is this the one with 16ns/38ns timing?
There is no such thing as a genuine PLA with 16/38 timing. This response speed is a replication implemented in PLAnkton to emulate the speed you would get with the 8700 rev. 2 along with an RC filter.

Hence, PLAnkton is a sort of 251064-01 with the CASRAM RC filter built inside it. It's active by default but the jumper on the underside allows you to go back to a 16/24ns config. It is recommended to do so with boards 250466.
Most of my C64's are PAL-versions, maybe there is the difference...?
From the information above I'd say you've seen pretty much all of them.
I'm also hoping to get more accurate results when I get a new logic analyzer (just ordered one with 500MS/s sample rate) , but it sounds strange if these measurements are off that much. Not saying it wouldn't be possible though. Also my measurements seem to match skoe's measurements on PLA Dissected, but then again he was using 200 MS/s logic analyzer like I did.

Anyway, timing PLA like you have done is perfectly fine and Commodore did that too (at least in 251064-01), I just chose different timing based on my findings.
Your measurements seem actually very close. It's just that your analyser will say 10ns if the delay is actually 14ns (just 1ns short of the next step) and 35ns if it is 38ns (just 2ns short of the next step) and so on.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

janilaa
Member
Member
Posts: 17
Joined: Fri May 19, 2017 10:37 am

Re: A new generation of PLA for the C64 is now available.

Post by janilaa » Wed May 24, 2017 2:19 pm

eslapion wrote:
Wed May 24, 2017 1:41 pm
I was going to say the 251064-01 is what you should look for. Some have 15-16ns on all outputs and some have 16/24ns. These can only work properly on C64 equipped with C204/R42 RC filter.
251064-01 isn't 8700r2 or is it? Isn't this MB112A101 which is being referred in schematic #251138?
I thought that only PLA's made by MOS/CSG are 8700r2.

User avatar
eslapion
Member
Member
Posts: 607
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: A new generation of PLA for the C64 is now available.

Post by eslapion » Wed May 24, 2017 6:17 pm

janilaa wrote:
Wed May 24, 2017 2:19 pm
251064-01 isn't 8700r2 or is it? Isn't this MB112A101 which is being referred in schematic #251138?
I thought that only PLA's made by MOS/CSG are 8700r2.
I don't think so. The schematic #251138 is for PCB ASSY 250407 and the PLA is called 7700-001 on this document.

The suggested value for for C204 when using MB112A101 is 82pf while all boards 250425 and 250466 use 150pf/82Ohms for C204/R42.

I found these 251064-01 mostly on boards 250466 and usually in C64c cases. They are pretty rare.

The weird thing is, they carry Commodore's chickenhead logo, not MOS or CSG.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

janilaa
Member
Member
Posts: 17
Joined: Fri May 19, 2017 10:37 am

Re: A new generation of PLA for the C64 is now available.

Post by janilaa » Wed May 24, 2017 7:35 pm

eslapion wrote:
Wed May 24, 2017 6:17 pm
janilaa wrote:
Wed May 24, 2017 2:19 pm
251064-01 isn't 8700r2 or is it? Isn't this MB112A101 which is being referred in schematic #251138?
I thought that only PLA's made by MOS/CSG are 8700r2.
I don't think so. The schematic #251138 is for PCB ASSY 250407 and the PLA is called 7700-001 on this document.
The suggested value for for C204 when using MB112A101 is 82pf while all boards 250425 and 250466 use 150pf/82Ohms for C204/R42.
I found these 251064-01 mostly on boards 250466 and usually in C64c cases. They are pretty rare.
I'm sure 251064-01 is MB112A101, because they have 112A101 written on them below the 251064-01 code.
Clearly Commodore had some plans on using this PLA on those 250407 boards because they mention it on schematic, but for some reason never did so.
(you actually can't really say 'never' when talking about Commodore) :D

At least most of the 251064-01's (MB112A101) seem to be made in 1983 (mine is 83, week 27), so that would match 250407 board's date also.

User avatar
eslapion
Member
Member
Posts: 607
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: A new generation of PLA for the C64 is now available.

Post by eslapion » Wed May 24, 2017 8:02 pm

janilaa wrote:
Wed May 24, 2017 7:35 pm
I'm sure 251064-01 is MB112A101, because they have 112A101 written on them below the 251064-01 code.
...

At least most of the 251064-01's (MB112A101) seem to be made in 1983 (mine is 83, week 27), so that would match 250407 board's date also.
I hadn't noticed that before but you are quite right. Also, having been made in 1983, they couldn't be 8700R2.

They look "futuristic" with the groove across the length, the circular recess in the center and they react faster than any and all other genuine PLAs so I guess I just assumed...

That being said, they do the job perfectly well.

On your eBay posting you mentioned:
- Correctly delayed timing on all output signals, not just the most critical #CASRAM like some competitor.
Well, you can also faithfully reproduce the amount of heat dissipated by a genuine PLA if you feel so inclined but I doubt this will make your product better.

Using a voltage regulator (with a hack to shift the voltage output up) and reproducing the 35 ns delay on all outputs as you have causes J-PLA to draw 28mA whn inactive and 35mA when it is active. That's 60% more than PLAnkton.

PLAnkton is 2ns faster than a genuine Commodore PLA on outputs other than !CASRAM...
Last edited by eslapion on Tue May 30, 2017 9:45 pm, edited 1 time in total.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

User avatar
eslapion
Member
Member
Posts: 607
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: A new generation of PLA for the C64 is now available.

Post by eslapion » Mon May 29, 2017 9:41 am

Special offer!

Buy one or more TOLB and get a 10% discount on up to 5 PLAnkton modules - you also save on shipping when you combine orders.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

User avatar
eslapion
Member
Member
Posts: 607
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: A new generation of PLA for the C64 is now available.

Post by eslapion » Thu Jun 08, 2017 4:33 am

janilaa wrote:
Wed May 24, 2017 9:38 am
Anyway, timing PLA like you have done is perfectly fine and Commodore did that too (at least in 251064-01), I just chose different timing based on my findings.
I am rather pissed here...

I checked J-PLA's page on eBay to see this nice technobabble...

- Correctly delayed timing on all output signals, not just the most critical #CASRAM like some alternatives.
- Uses genuine Xilinx CPLD bought from authorized dealer. Fast 5ns version used for most accurate timing.
- Integrated voltage regulator, constantly correct voltage for the CPLD. Also tolerates accidental insertion into SID-socket which has greater voltage.

For one thing, a voltage regulator, to me, is an indicator of lack of knowledge in electronics. It's just extra parts to impress gullible people.

For another, this '5ns for accurate' thing is major horse manure - genuine Commodore PLAs themselves have enormous response speed discrepancies; from 24 to 38ns - a 60% variation. Authentic 5ns CPLDs are needlessly more expensive, they also draw more power. He's just trying to legitimize using fake Chinese ICs that are half the price.

Third, PLAnkton is correctly delayed on all outputs. CASRAM requires more but otherwise, the low power mode and slew rate limiters do all that's needed. In fact, J-PLA has been measured to consume about 40% more power than PLAnkton.

Last but not least, the latest 'incarnation' of J-PLA suddenly have new parts added on the underside. Apparently a result of me posting more technical information here. If emulation is the sincerest form of flattery then I could definitely do without this one...

J-PLA exists because I posted the necessary technical information online on Melon64 nearly 2 years ago. Of course, Mr. Schönfeld and his friends dismissed all that as lunacy coming from Neptune. All Janilaa managed to prove is that he won't so quickly disregard information coming from outside the officially accepted views of the 'Old Boys Club'. He just grabbed information fetched through the hard work of other people and uses it to make his own amateurish replica.

Even the solders are inconsistent because they are made one at a time with an ordinary soldering iron using normal soldering procedures. No wave or drag soldering with professional methods and products.
Last edited by eslapion on Thu Jun 08, 2017 6:39 am, edited 1 time in total.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

User avatar
eslapion
Member
Member
Posts: 607
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: A new generation of PLA for the C64 is now available.

Post by eslapion » Thu Jun 08, 2017 6:31 am

Image
Genuine IC rated for 10ns. Solder all have the same thickness with 2 excess solder discharge points (solder thieves) for wave/drag soldering.

Manufacture date is 1701 - this chip was made in the 1st week of 2017. It was ordered from Digikey in April 2017.

Typeface is as large as space will allow and text is clearly visible.

---------------------------------------------------------------------------

Image
Counterfeit IC rated for 5ns. Solder have inconsistent thickness, some even have spikes. No accommodations for industrial soldering process.

Manufacture date is 1309 - this chip is 4 years old!!

Typeface is smaller and very difficult to read; this photo had to be taken with more lighting and longer exposure.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

Post Reply Previous topicNext topic

Who is online

Users browsing this forum: No registered users and 1 guest