DIY RAM EXPANSION

Nagging hardware related question? Post here!
tcat
Super Gold Card
Posts: 633
Joined: Fri Jan 18, 2013 5:27 pm
Location: Prague, Czech Republic

Re: DIY RAM EXPANSION

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

Toby, Brane, Dave, Mac, ... and All,

Guess what, it works now :D
Measuring all tracks by voltmeter, revealed a loose address line A10, resoldering on the connector side did it.

RAM test after boot really takes a while, slightly longer compared to unexpanded QL.

As I also put TK2 on CARE cartrige EPROM.
PRINT FREE_MEM gives
600064

But this value then slighly varies, after doing some BASIC, DIR, NEW, etc.
e.g. 599552

TCAT


tcat
Super Gold Card
Posts: 633
Joined: Fri Jan 18, 2013 5:27 pm
Location: Prague, Czech Republic

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.


User avatar
tofro
Font of All Knowledge
Posts: 2354
Joined: Sun Feb 13, 2011 10:53 pm
Location: SW Germany

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
User avatar
1024MAK
Super Gold Card
Posts: 584
Joined: Sun Dec 11, 2011 1:16 am
Location: Looking forward to summer in Somerset, UK...

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)
User avatar
Dave
SandySuperQDave
Posts: 2736
Joined: Sat Jan 22, 2011 6:52 am
Location: Austin, TX
Contact:

Re: DIY RAM EXPANSION

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

Score!

Congrats.


tcat
Super Gold Card
Posts: 633
Joined: Fri Jan 18, 2013 5:27 pm
Location: Prague, Czech Republic

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 405 times

ql520-Front.pdf
PCB Front Side
(19.12 KiB) Downloaded 287 times

ql520-Back.pdf
PCB Back Side
(15.8 KiB) Downloaded 253 times

ql520-brd.pdf
PCB Layout & Components
(31.31 KiB) Downloaded 292 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.


User avatar
Dave
SandySuperQDave
Posts: 2736
Joined: Sat Jan 22, 2011 6:52 am
Location: Austin, TX
Contact:

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.


User avatar
schombi
Chuggy Microdrive
Posts: 63
Joined: Mon Sep 24, 2012 7:11 pm
Location: Germany

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
Font of All Knowledge
Posts: 2950
Joined: Mon Dec 20, 2010 11:40 am
Location: Runcorn, Cheshire, UK

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
Gold Card
Posts: 257
Joined: Mon May 21, 2012 8:50 am

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:



Who is online

Users browsing this forum: No registered users and 5 guests