Lambda 8300/Power 3000 Mutlirom

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: Lambda 8300/Power 3000 Mutlirom

Post by 1024MAK » Tue Jul 23, 2013 9:39 pm

Looking good 8-)

Request for two PCBs sent via PM :D

Mark

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PokeMon
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Re: Lambda 8300/Power 3000 Mutlirom

Post by PokeMon » Wed Jul 24, 2013 11:18 pm

I think the extension Lambda Multirom should work with my 32k RAM extension with following change:
Pin 4 of the 74HCT32 (IC6) should be connected to Vcc (+5V), Pin 14 of IC6.
xrammod.jpg
xrammod.jpg (46.5 KiB) Viewed 500 times
This will disable automatic RAM detection which is neccessary if you want to use other ROMs than original ZX81 ROM.
But you can still use 32k RAM - it will not be detected automatically, only 16k.
You can activate 32k if you enter POKE 16389,192 and after NEW.
Or you simply patch byte $0004 of the ROM from $7F to $FF for a full RAM test.
This is simple when creating self ROMs.

Code: Select all

                                            ;; START
    0000: [0000] D3 FD                      L0000:  OUT     ($FD),A         ; Turn off the NMI generator if this ROM is
                                                                            ; running in ZX81 hardware. This does nothing
                                                                            ; if this ROM is running within an upgraded
                                                                            ; ZX80.
    0002: [0002] 01 FF 7F                           LD      BC,$7FFF        ; Set BC to the top of possible RAM.
                                                                            ; The higher unpopulated addresses are used for
                                                                            ; video generation.
    0005: [0005] C3 CB 03                           JP      L03CB           ; Jump forward to RAM-CHECK.
This is not yet proofed by Sascha but should work, I think.

sascha2000
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Joined: Fri Jul 22, 2011 1:13 pm

Re: Lambda 8300/Power 3000 Mutlirom

Post by sascha2000 » Thu Jul 25, 2013 8:23 pm

Hello,

I ordered today 24 PCBs. They will be produced within 3-4 weeks.

Price per PCB will be 7,74€ without components.

A component list I will provide soon here in this thread.

Best Regards
Sascha

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questarian
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Re: Lambda 8300/Power 3000 Mutlirom

Post by questarian » Fri Aug 02, 2013 3:20 pm

PokeMon wrote:I think the extension Lambda Multirom should work with my 32k RAM extension with following change:
Pin 4 of the 74HCT32 (IC6) should be connected to Vcc (+5V), Pin 14 of IC6.
Hmm... out of curiosity, sans the multirom, would your 32k extension work on a stock Lambda?

-John-

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PokeMon
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Re: Lambda 8300/Power 3000 Mutlirom

Post by PokeMon » Fri Aug 02, 2013 5:11 pm

Hmm ... I think so, probably yes.
Since it is compatible hardware.
But you need maybe the same hack with "Pin 4 of the 74HCT32 (IC6) should be connected to Vcc (+5V), Pin 14 of IC6".

I don't have schematics of Lambda and not sure if the expansion slot is connected with all signals :?:

sascha2000
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Joined: Fri Jul 22, 2011 1:13 pm

Re: Lambda 8300/Power 3000 Mutlirom

Post by sascha2000 » Thu Sep 12, 2013 8:32 am

Hello questarian,

>Hmm... out of curiosity, sans the multirom, would your 32k extension work on a stock Lambda?

I have tested the same. The 32k extension from pokemon does not work correctly on the Lambda without modifications.

Pokemon is working on this topic and as soon as he found a solution it will be posted here.


Here a picture what the Lambda displays with the 32k expansion:

http://forum.tlienhard.com/phpBB3/viewt ... =75#p10395

Regards
Sascha

sascha2000
Posts: 57
Joined: Fri Jul 22, 2011 1:13 pm

Re: Lambda 8300/Power 3000 Mutlirom

Post by sascha2000 » Tue Sep 17, 2013 12:48 pm

Hello,

the multirom PCB is now finished and available. A first version of the manual is present here:

http://www.eightbits.de/Multirom/Manual-v005.pdf

It is beta and not finished!!!!! So please be patient and update will come soon.

Cause my time is currently very very limited I will process the orders in the following days like:

1) I will send all persons who have ordered a PCB a PN with my paypal account. I will du this successive person by person. Please be patient it can take some weeks until your order is processed.
2) When the money arrived I will ship the Multirom PCB ... normally as a kit you must solder it yourself. (There are two exceptions of persons who helped me in the development).

Regards
Sascha

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: Lambda 8300/Power 3000 Mutlirom

Post by 1024MAK » Tue Sep 17, 2013 4:28 pm

:D 8-)

Mark

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: Lambda 8300/Power 3000 Mutlirom

Post by 1024MAK » Tue Sep 17, 2013 4:58 pm

This is the way that I assemble ribbon cable type IDC connectors:-
First I cut two pieces of softwood to size. I then sandwich the IDC connector between the two pieces of wood.
This sandwich is then put in between the jaws of a vice. I then carefully use the handle of the vice to close the connector until the "V" pins do their job and "bite" in to the ribbon cable, and the plastic clips snap in to place ;)

Mark

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sirmorris
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Location: oxon, uk

Re: Lambda 8300/Power 3000 Mutlirom

Post by sirmorris » Tue Sep 17, 2013 6:04 pm

For IDC connectors which have pins for direct connection to PCBs I do the same except I put 2 layers of stripboard over the pins so that they don't get damaged when I squeeze 'em...
--=== ZXpand+ ... A more moderner all-in-one upgrade solution for ZX81 ===--
* SD/MMC storage * 32K Hires-capable RAM * AY sound chip * Joystick port * Serial *
* BASIC enhancements - plug & play * Reset button * Auto-boot facility *

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