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Author Topic: 6Mhz and more... (Read 75036 times)

Offline pear

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Re: 6Mhz and more...
« Reply #105 on: 2017.December.14. 08:21:32 »
Small steps forward :)

The checklist:
Clock segment
* divider mod 2 done
* divider mod 3 done
* divider mod 4 done
* divider mod 5 done
* divider mod 12 done
* clock mux 8/1 done
* clock selector with phase synchronizer
* control circuit
* display
* management firmware
* address decoder

RTC segment
* battery backup (clock settings & ROM pages config)
* double buffer for local access
* address decoder

ROM segment
* address decoder with configurable memory pages

RAM segment
* address decoder

Offline pear

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Re: 6Mhz and more...
« Reply #106 on: 2017.December.17. 14:58:23 »
The first draft with maximum possible dimensions (155x76 mm or 6"x3").
The RTC optional will be DS12885 in SMD case or DS12887 with built-in battery.
The CPLD will probably have to be in an SMD enclosure (I need to a lot of pins).

I'm thinking about choosing the display: 3-digit LED 7-segment, or LCD 2x16 characters. In both cases, you need to cut a hole on the display.
The encoder knob will also be on top the housing.

The big square hole on the center of PCB is for new, bigger radiator for NICK.

Offline gflorez

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Re: 6Mhz and more...
« Reply #107 on: 2017.December.17. 22:03:06 »
These are very good ideas, the Nick chip square hole, and  the two RTC options on the same space.

What I don't understand is what do you mean with "a hole on the display". Where do you want to put the display and knobs?

155x76mm is an amazingly big area. You could even add all the EXDOS controller with the Gotek inside...

Offline pear

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Re: 6Mhz and more...
« Reply #108 on: 2017.December.18. 06:25:31 »
Thank you for your comment. This is the design stage when the assumptions can still be improved.

The hole is a hole :)
Somewhere you will need to place a display with information about the current status of all functions:
- system clock frequency,
- EXDOS clock frequency,
- configuration of ROM banks.
You can also display the date and time.
That is why I am inclined towards a small LCD or OLED display with 2x16 characters (about 20x50 mm).
It would be above the card.

The encoder knob must also be accessible to the outside.
EnterMice occupies the back. Edge connector on the right.
The top of the housing is left.

EXDOS controller and Gotek maybe it would be fit, but there is also a problem with space for external access to the USB connector and another display (maybe the display could be shared ?).
Besides, if you put everything at once on one board, the costs will get very high.
I will stay with the external EXDOS controller.

Offline gflorez

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Re: 6Mhz and more...
« Reply #109 on: 2017.December.18. 09:26:59 »
Nah, it was only a joke... imagine the internal entanglement with all the leads to the soldering spots.

-

About the hole, I think better without holes..., it would be better to pass a flat cable through some slit and stick a slim box with the display and encoder on top of the flat part of the EP top casing. I don´t like permanent modifications.

But however on this, the user has to decide.

-

I also like a full display. Imagine the clock and date on one line, still remains an entire line to put the two frequencies  and bank. ZozoTools have a choice to disable the top line clock, so it can be an enjoyable option.

Offline gflorez

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Re: 6Mhz and more...
« Reply #110 on: 2017.December.18. 09:45:06 »
About Rom banking, do you mean to take, for example, a 64kb bank from the FlashRom and make it visible on some zone of the 4Mb space? Or simply the position of the whole 512KB?

There is a scarcely used zone of 64Kb over the cartridge memory(08-0F) that is ideal for the first option.

Offline pear

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Re: 6Mhz and more...
« Reply #111 on: 2017.December.18. 10:54:37 »
The display has a tape connection, so it can be led out through the slot in the housing.
You'll need to make a housing for the display and encoder.
A good idea if someone wants to keep the computer case in original state (almost ;) ).

Bank mapping will be according to the list I once made.
ROM banks will be available by default at the standard ROM extensions segments (n0h-n3h where n is in range 0h..Fh).
But if there will be some conflict with the other device, it will be possible to disable such a bank or transfer it to another segment (assigned to a permanent, safe area, i.e. in which Zozo did not find any used segment ;) ).

I was also thinking about throwing the system EXOS ROM into Flash.
Instead of exchanging and wiring the chip on the motherboard.
A good idea ?

Offline geco

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Re: 6Mhz and more...
« Reply #112 on: 2017.December.18. 13:05:30 »
I was also thinking about throwing the system EXOS ROM into Flash.
Instead of exchanging and wiring the chip on the motherboard.
A good idea ?
I think it is a very good idea if it is possible, in this case EXOS ROM can be changed easily.

Offline gflorez

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Re: 6Mhz and more...
« Reply #113 on: 2017.December.18. 13:21:07 »
I have both EP installed with 128Kb flash chips, paged every 64kb bank with a switch. Zozo advised me to do it long time ago.

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This is an old picture. The cheap Winwond FlashRom produced some errors with the stock Z80. Zozo discovered that AMD was the best option for the hack.

Offline pear

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Re: 6Mhz and more...
« Reply #114 on: 2017.December.18. 13:29:22 »
I intend to use SST39SF040-70ns.

Offline gflorez

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Re: 6Mhz and more...
« Reply #115 on: 2017.December.18. 14:30:00 »
AMD and SST, they both still produce good legacy 5v chips.

The only problem is, Zozo planned to write an app to upgrade the 64kb bank selected. I don't know if AMD, SST or Winbond flash chips are written with the same protocol. The SD cartridge uses an AMD 512Kb FlasRom, much like the one I added to one of my Saint's 1Mb internal expansions, but smd. So the code for AMD is already done, he uses it when the cartridge firmware is upgraded.

Offline pear

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Re: 6Mhz and more...
« Reply #116 on: 2017.December.20. 10:14:27 »
About overclocking.
Because a square hole will allow access to NICK's, I invented to add a temperature measurement.
You can also set the overheat security.
If the set temperature is exceeded, the frequency would return to the default 8 MHz (or less until it cools down).

Offline Zozosoft

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Re: 6Mhz and more...
« Reply #117 on: 2017.December.20. 23:31:45 »
About overclocking.
Because a square hole will allow access to NICK's, I invented to add a temperature measurement.
You can also set the overheat security.
If the set temperature is exceeded, the frequency would return to the default 8 MHz (or less until it cools down).
Interesting idea, but I think it is not important. Nick still running on own independent ~14Mhz clock.
The bugfixed 08-47 Nick chips works good even if no heatshink (in some machines factory not installed).
The heatshink is a last minute bug fix idea when the 08-04 Nick chips are still not perfect, and the machine need to be released after one year delay...
(I checked: no difference at the operating temperature at the two Nick versions.)

Offline pear

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Re: 6Mhz and more...
« Reply #118 on: 2017.December.21. 06:03:55 »
Temperature sensor will be optional. Type of the display too (OLED or LCD, difference with backlight).
My NICK has blurred marks. The glue from the heat sink has washed them away.

By the way. Is it possible a faster CPU speed than 10 MHz ?
I still have 24 MHz available, which I can give to NICK (12 MHz for CPU).
« Last Edit: 2017.December.21. 06:19:11 by pear »

Offline Zozosoft

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Re: 6Mhz and more...
« Reply #119 on: 2017.December.21. 09:12:21 »
By the way. Is it possible a faster CPU speed than 10 MHz ?
I still have 24 MHz available, which I can give to NICK (12 MHz for CPU).
I tried 25 Mhz, but don't stable, worked only for about 1 minute. (Also tested with 20MHz Z80) I think at this point the system clock too fast for the Nick Z80 clock controlling circuit.

The 20 Mhz tested on many machines both with 08-04 and 08-47 Nicks, it is working fine.