DIY RAM EXPANSION

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tcat
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Re: DIY RAM EXPANSION

Postby tcat » Sat May 17, 2014 3:36 pm

Hi All,

I have a new observation, I have seen this code provided by Tobias in another thread pertaining to RAM performance.

Code: Select all

100 ram=RESPR(16): RESTORE 140
110 FOR p=ram TO ram+14 STEP 2: READ x: POKE_W p,x
125 t=DATE: CALL ram
130 PRINT "Test complete in ";DATE-t;" seconds."
140 DATA 28771,29439,20937,-2,20936,-8,28672,20085


It completes in 17 seconds, not sure, is it actually a good result?

Many thanks so far.
TCAT
Last edited by tcat on Sat May 17, 2014 5:56 pm, edited 1 time in total.


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tofro
QL Wafer Drive
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Re: DIY RAM EXPANSION

Postby tofro » Sat May 17, 2014 3:57 pm

TCAT,

that's about the fastest you can expect for 0 wait state uncontended RAM on the QL (same speed as ROM access) - See here for some comparison figures:
http://www.qlforum.co.uk/viewtopic.php? ... urbo#p6785

Congratulations!
Tobias


ʎɐqǝ ɯoɹɟ ǝq oʇ ƃuᴉoƃ ʇou sᴉ pɹɐoqʎǝʞ ʇxǝu ʎɯ 'ɹɐǝp ɥO
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1024MAK
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Re: DIY RAM EXPANSION

Postby 1024MAK » Sat May 17, 2014 5:34 pm

Well done TCAT Image Image Image

Good to see it is working well :D

Mark


QL, Falcon, Atari 520STFM, Atari 1040STE, more PC's than I care to count and an assortment of 8 bit micros (Sinclair and Acorn)(nearly forgot the Psion's)
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Dave
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Re: DIY RAM EXPANSION

Postby Dave » Sat May 17, 2014 5:40 pm

Score!

Congrats.


tcat
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Re: DIY RAM EXPANSION

Postby tcat » Wed May 21, 2014 6:39 pm

Hi All,

I am sharing back my work as you helped me with it.
It is not perfect, yet functional on my QL.
Soldering is required from both sides, not all pads need to be connected, and there are three vias.
I used therefore straight DIN connector, as this also appears easier to solder with a common non professional iron I have got.
I bent inner connector pins to an angle by tweezers and outer ones left straight, making connections with small lenghts of wire.

Many thanks
Tom

ql512k.zip
GAL Assembly JEDEC DOC files
(2.11 KiB) Downloaded 273 times

ql520-Front.pdf
PCB Front Side
(19.12 KiB) Downloaded 185 times

ql520-Back.pdf
PCB Back Side
(15.8 KiB) Downloaded 158 times

ql520-brd.pdf
PCB Layout & Components
(31.31 KiB) Downloaded 183 times


    eeschema (2010-03-14)-final >> Creation date: Thu 24 Apr 2014 07:33:24 PM CEST

    #Cmp ( order = Reference )
    | C1 0.33uF
    | C2 0.1uF
    | C3 100uF/10V
    | C4 0.33uF
    | C5 0.33uF
    | IC1 AS6C4008-55PCN
    | IC2 GAL16V8
    | P1 C64AB_FEMALE
    | U1 LM7805
    #End Cmp

    #Cmp ( order = Value )
    | 0.1uF C2
    | 0.33uF C1
    | 0.33uF C4
    | 0.33uF C5
    | 100uF/10V C3
    | AS6C4008-55PCN IC1
    | C64AB_FEMALE P1
    | GAL16V8 IC2
    | LM7805 U1
    #End Cmp

    #End List
Last edited by tcat on Thu May 22, 2014 7:53 pm, edited 1 time in total.


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Dave
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Re: DIY RAM EXPANSION

Postby Dave » Wed May 21, 2014 8:14 pm

Thanks for publishing this, tcat.

You might want to add your JEDEC for the GAL you used, and a list of parts. This would then be a complete package anyone could put together. Also, by publishing your JEDEC and algorithm people can maybe modify it and feed back into your project.

If people are interested in building this, I have the majority of the parts (not the PCB or DIP version of the RAM though) and if tcat is interested, I'd be happy to put a kit together for those who want to make their own PCBs.


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schombi
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Re: DIY RAM EXPANSION

Postby schombi » Thu May 22, 2014 8:12 am

Don´t forget to offer fully populated boards for people that can only replace a capacitor on a Spectrum, like me ;)


Derek_Stewart
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Re: DIY RAM EXPANSION

Postby Derek_Stewart » Thu May 22, 2014 9:09 am

Hi,

I was going to make a PCB for myself.

Would there be a demand for more?


Regards,

Derek
Paul
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Re: DIY RAM EXPANSION

Postby Paul » Thu May 22, 2014 2:07 pm

I guess this depends on when Dave will be able to deliver his RAM, and on your price :mrgreen:


thorsinclair
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Re: DIY RAM EXPANSION

Postby thorsinclair » Thu May 22, 2014 3:57 pm

Slightly off topic: when (if) will be available the rom port version of the QL SD which is compatible with the Gold Card? If I can keep my Goldcard I would not need any RAM extension in order to work with QL SD.

;)



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