Posted By
MCes
on 2022-09-26
12:24:22
 |  C16 JUGGLER board is under development.....
OK, "JUGGLER" is a strange name for a project,
but I don't find a good name for this board that is...
1) 16/64k RAM expansion (based always on static RAM, on C16 matherboard 4 chips can be desoldered for lowering absorption/heating inside)
2) CPU replacement (a specific revision of CPU4C16 project) based on N-Mos 6502"A+" core
3) The task of the "input keyboard/joystick port" (normally done byTED chip) is synthesized on board,
so the C16 will work fine even if the TED used has problems with its port (LATCH problem: mixing the two signals of the joystick, reading the keyboard ...)
For the starting test I'm using a TED that otherwise write "π" continuously.... (thanks to @Retroshire )
forum/42748
The TED port can be easily damaged by ESD by plugging / unplugging the joysticks,
as the CPU port can be damaged by ESD plugging / unplugging the external drive (tape / disk) even if the devices are turned off!
On the CPU4C16 the CPU port is synthesized by CPLD so the N-Mos CPU core cannot be reached by the discharges of the external pins, and now the same is for the TED port!
Now, the bigger question is:
what other name would suit this project better?
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Posted By
MMS
on 2022-09-26
15:18:22
 | Re: C16 JUGGLER board is under development.....
Wow, a C16 board with long term reliability in focus! I suppose it was not in Commodore's top focus points. 
I do not want to be rude, but even Bil Herd told at a conference, that noone at Commodore though anyone will use them after 5 or 10 years.
These were consumer products with a few years lifecycle in plan.
Maybe it worth to mention you can swap the old ROMs with EEPROMs for the lower power consumption, lower heat may also play a role in longer lifetime.
Also worth to mention to change the original C16 PSU to a modern stabilized 9V one.
Back to your original question: maybe "SolidC16" or "C16oncrete" ?
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Posted By
MIK
on 2022-09-26
18:02:16
 | Re: C16 JUGGLER board is under development.....
How about..
C16 Monty board, as in The Full Monty. 
PS.Juggler reminds me of the early 2000's - CD burining software aka DiskJuggler.
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Posted By
MIK
on 2022-09-27
08:44:43
| Re: C16 JUGGLER board is under development.....
I wish, just turned 52 lol. Ha I remember that juggler.
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Posted By
MCes
on 2022-09-27
12:21:25
| Re: C16 JUGGLER board is under development.....
And for the curious boys....
NOTE: "C16MultiMod" is written on the PCB
May be that is possible to have a pin free on CPLD, in this case it will be possible...
1) INPUT: a jumper for not drive the DATA BUS if CPU is writing on $FD1X
(this prevent a bus conflict with U11 but the "@SukkoPera" external port can't be used at this address)
2) OUTPUT that detects a write operation on $FD3X: connecting it to an external register and 8 diodes (to be integrated on the JUGGLER PCB) the 6529B keyboard port is replaced!
(another custom chip replaced...)
Option "1)" or option "2)"?
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Posted By
MIK
on 2022-09-27
18:09:00
| Re: C16 JUGGLER board is under development.....
Is that a memory jumper on the left for 64k & 16k configuration? Does the tape port still function as I believe some newer CPU's disable it?
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Posted By
gerliczer
on 2022-09-28
03:13:39
| Re: C16 JUGGLER board is under development.....
@MCes: Larger CPLD and both?
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Posted By
MCes
on 2022-09-28
09:10:52
| Re: C16 JUGGLER board is under development.....
@gerliczer
I noticed that the CPLD pin that now is free is an "only input" pin, so I think that it will be the "$FD1X Write Disable" pin...
I want not to rework completely the PCB or make great changes, may be that the old PCB will be easy assembled with this new feature without a second PCB batch.
@MIK
Yes, on the left there is a jumper (or remotable switch) for choosing the memory size: 64K(opened) or 16K(closed), both sizes are on static RAM, so on motherboard 4 chips CAN be desoldered (for lowering the heat inside the C16): 2xDynamic Ram and 2x74LS257 memory multiplex, because the original RAM remain constantly deselected.
The "newer CPU" that disable 1 bit of the TAPE PORT is only a bad patch for using directly a MOS 6510 as CPU, and this is NOT my case.
Remember that Commodore was already producing 6510 when their engineers started the 7501/8501 production, do you think that Commodore didn't know if an 6510 can fit a 264 machine?
Solutions on JUGGLER, as on CPU4C16 and CPU4PLUS4, match the busses timings and functionality of the 264 machines included the reading of the tape keys
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Posted By
MIK
on 2022-09-28
21:25:32
| Re: C16 JUGGLER board is under development.....
Cool.
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Posted By
MCes
on 2022-10-06
03:02:50
| Re: C16 JUGGLER board is under development.....
OK, now the prototype:
1) use the SRAM on board
2) keyboard is well read
3) joysticks are well read (with a damaged TED: the TED parallel port activityes is moved from TED to JUGGLER)
4) CPU is a TED slave, as he has to be
5) CPU parallel port work: tape (also turbo) and disk (also jiffydos, krill loader, pet rescue, MOS, ecc...) work well
Next steps:
1) more functionality tests
2) signals check with oscilloscope
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Posted By
TLC
on 2022-10-06
09:49:11
| Re: C16 JUGGLER board is under development.....
Wow!  Very good progress here!
Some loose idea regarding functional testing... maybe useful, maybe not. Recent 8501 replacements (i.e. standard 6502 + additional logic) generally still fail to run a few programs. One good example is High Technology by Methabolix. I don't know the exact reason for that, I have no such replacement cards yet so that I could test that myself. I merely suspect that there could still be some issue with regards to how the onboard I/O port is implemented. It's known that Coby used to use both a fastloader and a code protector very picky about timing and exact I/O behaviour. ( High Technology already fails to run if one of the datassette buttons is left pressed...) Maybe it'd make a good candidate to be part of some compatibility test "suite".
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Posted By
siz
on 2022-10-06
11:08:21
| Re: C16 JUGGLER board is under development.....
@TLC: You are probably right about High Technology: I just tested it on my configuration and indeed it does not work. I have to find the culprit later (right now I don't have the time for that) but my configuration is "exotic": plus/4 with 6502 plus 4 (with 512k RAM expansion), JiffyDOS, UK1541 as drive emulator (with JiffyDOS). The "Time protector" always finished correctly but mostly the load (and demo) does not start. One time it did so who knows.
@MCes: how do you plan to find expansion port connector for your motherboard? AFAIK that's the only impossible to source part beside TED, of course.
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Posted By
gerliczer
on 2022-10-06
12:12:28
| Re: C16 JUGGLER board is under development.....
I can attest too to High Technology being finicky. I have a 1541-II that back in the day, depending on which outlet I plugged it in, was or wasn't willing to load the first part successfully. Interestingly, only the first part produced the symptoms for me. So, if I plugged it to the "wrong" outlet and tried many-many times there were exceedingly rare cases when it loaded and ran the whole demo successfully after all. IIRC.
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Posted By
MCes
on 2022-10-07
03:35:15
| Re: C16 JUGGLER board is under development.....
@TLC
I tested "High Technology" on my CPU4C16 (the same for CPU4PLUS4) and it work fine,
the first attempt on "JUGGLER" did not work perfectly, but comparing the internal structure of the two CPLDs I found the point....
Now I can load it with jiffydos as well (for the first boot file) and everything works fine stably.
 
@siz
Why do I need to find the port connector?
The JUGGLER is a little board that has to be placed inside the C16 (without use of solder...).
It need only to remove the old CPU (that will be NOT used) and the TED (TED also with problem on its parallel port),
than plug the JUGGER on the free sockets and place on it the TED chip: all will be in working condition....
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Posted By
TLC
on 2022-10-07
04:20:51
| Re: C16 JUGGLER board is under development.....
@MCes Looks perfect indeed!
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Posted By
Litwr
on 2022-10-08
00:58:53
| Re: C16 JUGGLER board is under development.....
It seems that thing can fix my broken C16! It sounds great.
But have you tested this board with HNY2013 and 231c?
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Posted By
siz
on 2022-10-08
09:59:07
| Re: C16 JUGGLER board is under development.....
@MCes: I am stupid and I was not looking at which topic I'm posting and somehow thought that we are talking about the replacement C16 board
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Posted By
MCes
on 2022-10-14
10:25:37
| Re: C16 JUGGLER board is under development.....
I tested the JUGGLER as a CPU, as a keyboard/joy port, as RAM expansion..... and I am satisfied.
The proto PCB need to be "patched" with a resistor network and 2 wires, so if only few people want a JUGGLER I can use the old PCB, but if people ask for more of 5 pieces in total than I can draw and order a new batch of PCBs.
The JUGGLER is better than the sum of:
1x CPU4C16
1x 64K SRAM expansion
1x ESD joy ports protector (TED port fixed: replaced!)
For the JUGGLER I ask 39€/pc, Is someone interested in it?
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Posted By
MMS
on 2022-10-16
18:17:08
| Re: C16 JUGGLER board is under development.....
you know I like your upgrades. :-) Due to the ESD protector and the two remaining non-operating Plus/4 I own I am interested too.
Just a curious question I raised previously in a PM:
if this is not a real 6502 CPU, and the CPU is just the slave of the TED, during the periods the CPU works alone on the borders, there is no way to make to add to the package a switchable CPU FRQ doubler or more? If the "CPU" can manage such speeds.
It would not make the project much more expensive, on the ebay it is close to 1€/pc
https://swharden.com/blog/2016-08-31-ics501-simple-frequency-multiplier/
AFAIK noone ever made a CPU upgrade option for the Plus/4, while other 8 bits had it.
It could be the first on this platform, and could provide really something new:
-C64 had the 4MHz external 6502 and the CMD 20MHz SuperCPU
(Ruud Baltissen developed an internal replacement with 65816 CPU with potential 16MB mem, but did not offer speed increase http://www.baltissen.org/newhtm/02to816.htm)
-BBC Micro had the CPU cards with different, fast CPUs (including (Z80 and 6502 @4Mhz)
-C128 had the integrated Z80, though it was pretty slow, in practice only 1MHz , but 7502 could be switched to 2MHz
-Atari 800XL has 6809 upgrade, but no programs made to use it.
While the SuperCPU and the C128 Z80 required special programming, in this case nothing to be added, and it comes from the special architecture the 264 series has:
the CPU simply would work faster on the border, than normal (instead of the 1.76MHz the 2x means 3.5MHz or maybe the 5x 8.8 MHz).
I mean if a higher than 1MHz comes from the TED, it would be doubled, 5x or so.
In this way it would not influence the picture, sound or sync or any other things, as handled by the TED on his own frequency.
Different CPU speeds is a huge problem on other platforms (due to video and sound issues), but (I think) it is not a big issue in our case.
How it could be used on our platform?
-Better quality digi SID emulation by higher sampling rate.
-More time for proper (and more) soft-sprites
-4 channel 4bit digi tracker as seen on ZX Spectrum with their 3.5MHz CPU (3.5MHz with 6502 code would be more than enough).
https://www.youtube.com/watch?v=g_Ox3fSCSEw
-Better decompression times
I hope you see my point and the potentials of it... If the slewed down CPU in the TED periods would not cause a problem.
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Posted By
MCes
on 2022-10-17
12:31:22
| Re: C16 JUGGLER board is under development.....
@MMS
there are a lot of reasons for not trying to "overclock" the CPU:
1) the machine will be different so SPECIFIC software have to be wrote for this (not compatible with a standard machine)
2) the machine (RAM, TED,the BUSses) remain a 2MHz machine, so you can speed up it only making fast the internal work of cpu (as instruction that use some cycles to elaborate the result..) but the gain will be very limitated....
Better can be a board to collocate on TED socket that integrate a CPLD, a fast (and big) RAM and a W65C02S (13MHz 6502 based Cmos CPU: no illegal opcode) that can be used as co-processor (also graphical).
RAM could be shown to TED (in specific timings) in selectable blocks.
These resources could be made available to the programmer who could use them in various ways,
it will be a 13MHz 65c02 computer that use the TED as joining ring with the old 2MHz machine for a parallel cooperation (obviously the fast RAM can be loaded by old CPU also with the code for the new CPU)
and the programmer will decide wich tasks are for the 8501 and which for the W65C02S
But remember: this will be a NEW computer, different from any other that needs specific software....
Personally I think these solutions don't make sense.
As you can see my modifications try to get the best out of our computers by staying within the perimeter that mum Commodore designed for them....
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Posted By
MMS
on 2022-10-17
17:33:54
| Re: C16 JUGGLER board is under development.....
@MCes
OK! Thank you for the detailed answer!
(1) BTW as you plan to use SRAM, the access could be several times faster than the current DRAM
2) the CPU upgrade you suggested sounded something similar to the one worked in the BBS Master AFAIS) )
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Posted By
gerliczer
on 2022-10-18
00:16:29
| Re: C16 JUGGLER board is under development.....
@MCes: Do I get it right that in your opinion SuperCPU for the C64 and C128 doesn't make sense? Because what MMS described in his post was the implementation of such an extension within the limits of the 264 series.
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Posted By
MCes
on 2022-10-18
11:21:24
| Re: C16 JUGGLER board is under development.....
@gerliczer
I think that the goal of a "264 SUPER CPU" or "264 coprocessor", etc.... can be a good piece of engineering but it has no sense for me:
the new 264 will be another computer that need new SPECIFIC software.
I don't care, but I understand it may interest someone else
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Posted By
unclouded
on 2022-10-18
17:46:39
| Re: C16 JUGGLER board is under development.....
@MCes please put me down for one of these boards when they're ready. I'm not on here often so I'll confirm by e-mail.
My vote for the name would be "Anti-statiC16".
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Posted By
gerliczer
on 2022-10-19
00:26:53
| Re: C16 JUGGLER board is under development.....
@MCes: I think, I understand your reasoning, although I find it a little bit strange as any home-brew expansion needs SPECIFIC software. Following your logic e.g. connecting an SID-card or a custom multi-bank ROM cartridge will turn these machines into another computer.
Nonetheless, it is very much your right to feel any way your personality makes you feel and I respect that and your opinion.
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Posted By
MCes
on 2022-10-19
10:43:44
| Re: C16 JUGGLER board is under development.....
@gerliczer
This is my view:
The "@SukkoPera external user port" is an EXPANSION cart that adds to C16 a part that was foreseen in the PLUS4 version.
A multi-bank ROM can be the basis for a multi-game cartridge that has no compatibility issues.
The SID cart is not an expansion: it has to be considered as an AUDIO PERIFERIC.
A new game should be created in different versions which will be incompatible with each other: for audio from TED, for audio from SID and for audio from AY3-8910 ..... it's crazy!
If the modification distorts the machine so much that it is not compatible with the old software, then you must first stop and think if it is a right step.
It is different if you want to specialize your machine in a specific task with specific software and hardware, but you will build a new computer based on the old one; simple to develop but a unique piece in the world ...
Example:
a board that fit intoTED and CPU socket, with on board a W65C02S (or a W65C816S) clocked to 10..12MHz and a fast SRAM, system slow down when it has to access to the "old" bus peripherals, it will increase a lot the speed with the cost of:
1) CPU will be a Cmos... less heat but not illegal opcode permitted: it will be not compatible with the recent software
2) the programmer must create SW exclusively for this modified C16 version: the SW cannot work correctly without this mod, if the SW worked anyway then the modification would be useless ...
And the best implementation for a TURBO-CPU is for gaming....
A TURBO-CPU for C16 (not for PLUS4: it need some physical space) is possible, it can be a good artist work (an engineering exercise) but I don't see a goal for it....
I reached the limit of this argument with the work that i was developing for the VIC20, the DREAMCART:
VIC20 has memory holes to be equipped externally with game ROM cartridges or with RAM expansion to load new large games from disk/tape.
Recent games need to be loaded into RAM expansion and not ROM, making them non-implementable in cartridges, so programmers can't create the cartridge version of their games ...
DREAMCART expands all the RAM possible and hides a banked ROM, at startup the SW in the ROM copies the contents of the ROM into the RAM and then the game is started as if it had just been loaded from disk on an RAM-expanded VIC20 ....
It can be seen as a different VIC20 architecture, but the user have in his hand only a standard VIC 20 and a "standard" cartridge..... (no specific computers/modification)
(also the game is simply a .PRG file from disk image... not another version has to be developed!)
http://sleepingelephant.com/ipw-web/bulletin/bb/viewtopic.php?f=10&t=9950
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