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Author Topic: EPROM/Flash ROM/SRAM expansions (Read 75802 times)

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #75 on: 2014.February.10. 23:50:19 »
At last the component store didn`t find the flash ROMS. I`ve ordered programed to Zozo.

-----------

Al final Merchan(Alcobendas) me estaban dando largas con las memorias y se las he encargado programadas a Zozo.

Offline Zozosoft

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #76 on: 2014.February.12. 08:56:20 »
Quote from: gflorez
I`ve ordered programed
It is on the way!

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #77 on: 2014.February.18. 11:44:33 »
The Flash ROMs arrived just now.

I've checked one last time the changes before enter the chip in the socket....


And it works....... but the old EXOS inside the EP makes odd thing.


It's time to change it to the new version I have also received from Zozo.

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #78 on: 2014.February.18. 12:05:34 »
Please Zozo, next lesson:

 From where of the main board I can take the required -WE signal?

And, how I select the upper or lower 64k part of the 128K flash ROM? Directly 0v / 5v to the 2 pin(A16) of the chip?

Offline Zozosoft

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #79 on: 2014.February.18. 12:43:31 »
Quote from: gflorez
From where of the main board I can take the required -WE signal?
From the expansion bus connector pin B2 (at the top, counting from the keyboard)

Quote
And, how I select the upper or lower 64k part of the 128K flash ROM? Directly 0v / 5v to the 2 pin(A16) of the chip?
Yes.
Or put a Pull-up resistor (10K) to pin 2 and pin 32, and wire from pin 2 and GND go to the switch. When the switch on then A16=0, when open the resistor make it to 1.

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #80 on: 2014.February.18. 15:22:00 »
Now I remember long ago I fixed that TAPE-IN Relay...

Sorry for the bad quality...
« Last Edit: 2014.February.18. 17:07:36 by gflorez »

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #81 on: 2014.February.18. 17:29:40 »
Changed the 5v to pin 31 of the internal ROM socket.
I added an A15 address to the pin 3 , directly from the pin 5 of the Z80.
Then 0v to pin 2  to test.

Power on, but the screen shows only moving strips of colours... 

Meanwhile I returned to insert the original ROM...

Offline Zozosoft

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #82 on: 2014.February.18. 17:41:33 »
A15 from Z80 isn`t good! Need from system bus because of the memory paging! It is on the pin B9
« Last Edit: 2014.February.19. 09:53:03 by szipucsu »

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #83 on: 2014.February.18. 19:23:43 »
Of course, Nick pagination.... newbie error...

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #84 on: 2014.February.18. 21:10:39 »
Fixed, but...... always there is a but.

The system starts but hangs every now and then.

Offline Zozosoft

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #85 on: 2014.February.18. 21:30:04 »
VCC disconnected from socket Pin 1 (Flash ROM pin 3)?

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #86 on: 2014.February.19. 00:07:42 »
Yes, pin 1 from socket now is disconnected(I bended the chip pin 3 and soldered directly to address A15 on bus expansion)

I left the leads too long. Tomorrow I`ll shorten  them to test.

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #87 on: 2014.February.19. 16:56:20 »
The EP without the Microteam EXDOS works good.

The problem isn't with the internal Flash ROM modifications.

(E)XOS reset or (N)ormal reset gives error with the card connected, but not with (A)dvanced reset nor (C)old reset:

Offline Zozosoft

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #88 on: 2014.February.19. 17:02:04 »
Quote from: gflorez
The EP without the Microteam EXDOS works good.
Now the onboard Flash ROM installed succesfully?

Quote from: gflorez
(E)XOS reset or (N)ormal reset gives error with the card connected, but not with (A)dvanced reset nor (C)old reset:
Very interesting :oops:
Which segments marked as bad?

Offline gflorez

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Re: EPROM/Flash ROM/SRAM expansions
« Reply #89 on: 2014.February.19. 17:52:31 »
Yes, the internal ROM works good, from the fist time, but I don't tested it without the EXDOS card until today....

The bad segments are: BF-B0, 9F-90, 3F-30 and 1F-10.

And if I extract the SRAMS, zero errors, but the 512k Flash ROM may have the same errors of addressing, isn't it Zozo?
« Last Edit: 2014.February.19. 19:56:47 by gflorez »