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Author Topic: 6Mhz and more... (Read 74886 times)

Offline pear

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Re: 6Mhz and more...
« Reply #195 on: 2018.February.21. 16:08:43 »
Perfect fit :smt026
Pegs hit perfectly :)
The PCB just requires only a gentle grinding at near the reset button.
Can be slowly assembled.

Offline Zozosoft

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Re: 6Mhz and more...
« Reply #196 on: 2018.February.21. 16:42:09 »
Very exciting!

Offline Tutus

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Re: 6Mhz and more...
« Reply #197 on: 2018.February.22. 09:26:41 »
Very nice! I'm looking forward to it. :)

Offline pear

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Re: 6Mhz and more...
« Reply #198 on: 2018.February.24. 17:12:26 »
There is some progress.
All power sources work properly (+ 5V, + 3.3V, -5V).
But I found a few minor mistakes.
First of all L-connector has a shifted connector EX2 by one pin to the right. I will have to correct and order again :|
Pads for SMD quartz generators are for version 3.3V instead of 5V, so they can not be used. On this PCB may be used only generators in the DIP housing.
And at last, was supposed to be a socket for the CR2032 battery, and by mistake it is for CR1632. This is the smallest problem.

My garage is so cold that even the camera on the smartphone refused to take pictures :oops:

Offline gflorez

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Re: 6Mhz and more...
« Reply #199 on: 2018.February.24. 19:52:06 »
Pear, come here to sunny Spain a month or two...

Offline pear

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Re: 6Mhz and more...
« Reply #200 on: 2018.February.24. 20:09:00 »
I'll manage somehow. I have to.
I have yet to mount the CPLD and move to my home.
I'll start to write tomorrow a firmware.

Offline gflorez

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Re: 6Mhz and more...
« Reply #201 on: 2018.February.24. 23:44:33 »
There is an aspect of the turbo hack not enough spoken.

On the description Zozo says:

On some motherboards some problem can be found with the video memory on turbo speed, then short circuit R12. On higher speed (10MHz :-) ) also needs removing C7.

I have made this midification to my two Enterprises and as a result sometimes at 4Mhz the memory test gives some errors, but zero errors at 10MHz. Not a big problem, ghost errors only happen on not installed memory.

What if you include some sort of commutation for R12 and C7?

Offline pear

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Re: 6Mhz and more...
« Reply #202 on: 2018.February.25. 08:19:11 »
I have not seen this before. It's a pity, because it's a bit too late for such modifications, but ...
Has anyone tried to insert capacitor of value 47 or 33pF as C7 (the R12 resistor should remain in place) ?
How then will go at 10 MHz ?

Offline gflorez

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Re: 6Mhz and more...
« Reply #203 on: 2018.February.25. 09:46:28 »
I can try it tomorrow.

Thanks.

Offline Zozosoft

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Re: 6Mhz and more...
« Reply #204 on: 2018.February.25. 12:14:32 »
short circuit R12... removing C7.
I do it always.

Quote
Not a big problem, ghost errors only happen on not installed memory.
This is because no pull ups on the data bus. Then totally undefined which data can be read from unused memory (and I/O) space. Usually FFh, but not guaranted. It mainly depened about the CPU. With CMOS Z80 are usually come the floating bus problem (ghost bad segments). But in some machines still exist the problem with the original NMOS CPU.
If the floating bus problem present then some games can hang up. Because using IM2 mode with non complete jump table (assume FFh from the non definied data bus).

The right solution add pull-up resistors to the data bus. As I wrote it here: https://enterpriseforever.com/hardware/6mhz-and-more/msg37473/#msg37473


Offline gflorez

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Re: 6Mhz and more...
« Reply #205 on: 2018.February.25. 14:36:44 »
But I remember to put pull-ups on both Enterprises...

I will reassure it tomorrow.

Offline pear

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Re: 6Mhz and more...
« Reply #206 on: 2018.February.26. 07:26:47 »
There are signs of life :)
Part of the circuits are already working.
There are correct clock signals for the microcontroller, EXDOS (after reset 8 MHz) and a control signal of 1 MHz.
Somewhere is a short circuit between the LED control pins and the clock output for the system.
The CPLD assembly with such a density of legs is a real nightmare (especially stiff with cold fingers).
Each one pin is a new gray hair :evil:
Unfortunately, I have to wait with the amendments until the frost will let go.

Offline gflorez

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Re: 6Mhz and more...
« Reply #207 on: 2018.February.26. 10:46:20 »
About the ghost bad segments, I have tested it thoughtfully now, and they only appear on my "new" Enterprise on 4MHz. I installed pull-ups on both machines as you suggest on the description, so it can be a human error....

Offline pear

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Re: 6Mhz and more...
« Reply #208 on: 2018.March.07. 06:14:37 »
Taking advantage of the opportunity that the frost for a moment has eased (in the garage was the temperature close to the top shelf in the refrigerator :mrgreen: ) I removed weak connections and short circuits.
All signals from the CPLD are generated correctly :smt026
Unfortunately at the first connection, I mistakenly connected the power ground and damaged the buffer (this is here to protect the rest of the components and as you can see works). I need to replace it :oops:
Finally, I can start to fun with the firmware.

Offline Zozosoft

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Re: 6Mhz and more...
« Reply #209 on: 2018.March.07. 09:46:25 »
Finally, I can start to fun with the firmware.
When it is near to be finished: Can I get one to develop EXOS/EXDOS support?
How can the firmware be updated? In the same way as the EnterMice? Or are other chips used? Needed something programming interface?
« Last Edit: 2018.March.08. 11:18:16 by szipucsu »