electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
 Forum index » DIY Hardware and Software » Circuit Bending
Successful 2x Memory Expansion for Casio SK5 and SK8!!
Post new topic   Reply to topic Moderators: dnny, v-un-v
Page 1 of 1 [2 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
gmeredith



Joined: Jun 28, 2006
Posts: 82
Location: Tasmania, Australia
Audio files: 1

PostPosted: Wed Aug 02, 2006 10:51 pm    Post subject: Successful 2x Memory Expansion for Casio SK5 and SK8!! Reply with quote  Mark this post and the followings unread

Well, it's been a very successful and productive afternoon! I've now got a fully working, SK8 with DOUBLE the sampling capacity of the original!

Here's my step by step How-To for the SK5 and SK8.

2x Memory Expansion for Casio SK5 and SK8 -- by Graham Meredith

This was an attempt for me to understand memory chip control, and how to access them. Plutoniq9's 32x memory expansion in the Yahoo Casio SK Groups is a much larger, better and more elegant way of doing memory expansions, but I wanted to have a go at this one first, and then try his one when I got mine working.

I now have 2 RAM chips installed in my Casio SK8 - the original SK8 chip (the uPD43256), and the new chip (the Dallas DS1230Y-150), stacked on top of each other, with a switch and 2 resistors to switch between the 2 chips.

This has given me 2 separate banks of 4 samples - the 4 from the original chip, and now an extra 4 from the top bank.

Equipment

Soldering iron, 15W (no greater – can damage the circuit tracks by excess heat)
Solder
Antistatic wrist band and cable
Wire cutters

Materials


Dallas DS1230Y-150
http://www.futurlec.com.au/test13.jsp?category=ICDALLAS&category_title=Dallas%20Semiconductor&main_menu=IC&sub_menu=ICDALLAS

Or:

Texas Instruments BQ4011Y: http://focus.ti.com/docs/prod/folders/print/bq4011y.html

Hookup wires, insulated, of different colours
DPDT toggle switch
10k ¼ watt resistors – 2 of.

Procedure:

Put on the antistatic wrist band and cable, connect the cable somewhere to earth, such as a water tap. This will prevent static discharge building up and damaging your chip.

1. Study the pin out diagrams for each chip below. Also, examine the actual chip when you get it. Make sure you can identify which is pin 1 on the chip (it has a little embossed circle next to it with a “1” in it on the top of the chip).

2. Unplug the Casio from the power adapter, and remove the batteries. Now, switch the Casio ON to drain any residual power left in the circuits

3. Making sure the chip is placed the correct way around, solder the new chip directly onto the top of the old one, pin for pin, except for the CE pin (or CS pin on the original chip), which I bent out horizontally away from the other pins on the new chip. Disconnect the old chip's CS pin by de-soldering its track on the circuit board and isolating its pin. Please have a look at the pin outs diagrams below, and study them.

4. Solder 10k resistors to each of these CE/CS pin legs of the 2 chips. These 2 resistors then go to the 2 centre terminals of a DPDT toggle switch via lengths of insulated wire - see the wiring diagram below.

5. Solder the CE signal track wire to the CE pin track on the track side of the board, anywhere near where you desoldered the CE pin from the original chip (make sure you don't accidentally reconnect the CE pin to the circuit track again).

6. Solder the +5V supply wire directly to the exposed pin 28 leg (the +5V Vcc pin) of the original chip, as a convenient +5V supply for the switch.

7. That's basically it!


Using the sample banks

Put some batteries in the Casio, or connect it to the power adapter. Put the toggle switch in the bank 1 position (accessing the original RAM). Record some samples on the pads - any samples, using the inbuilt mic, for example. Record 4 short samples - one on each pad. Play them to confirm the recording went OK.

Now, switch the toggle switch to the bank 2 position (accessing the NEW RAM). Record 4 samples in the same way. Play them to confirm the recording went OK. Switch back to bank 1. Your bank 1 samples should still be there, ready to play!! If you have batteries installed, you can now switch off the keyboard. Switch it back on – bank 1 samples should still be there. Switch to bank 2 – they should be there also!

Minor Issues and Limitations

Memory loss from flat batteries

There is a catch, in that once you've got it working, and you've recorded samples on both banks, if your batteries go flat, the sampler will “appear” to have lost the samples stored in the new 2nd chip. It will sound the default “empty sample” sound on each pad. It actually hasn't, they're still there. But the Casio's processor has lost its directory info about where to find the samples when the batteries went flat.

To restore them, put the toggle switch in the bank 1 position (accessing the original RAM). Record some samples on the pads - any samples, using the inbuilt mic, for example, but in the same layout that you recorded the samples on the new bank chip - ie. samples 1 and 2, long or short, samples 3 and 4, long or short. Play them to confirm the recording went ok.

Now change the bank switch. Your 2nd bank samples should now be there, just as you left them, before your batteries went flat. So, you only have to do this if the battery power fails, or if you use an AC adapter without batteries in the keyboard. Normally, both banks samples will be there as soon as you switch it on, with good batteries installed. The new chip remembers the samples EVEN when there is no power or flat batteries.
Remember, though, that the OLD chip won't - it will remember them when switched off only while you still have good batteries in it, just like it always did.

I have installed rechargeable nicad batteries in my SK8, and soldered in an extra charging socket, so I can recharge without having to disconnect the batteries and remove them, when I hear them start to go flat.


Different length samples in different banks

If you recorded 4 short samples in bank 2 first, and then 2 long samples in bank 1, you will find the sample playback a bit strange when you shift back to bank 2. Try it – it makes for some interesting sample playback. Sample 1 pad will play back both sample 1 and then sample 2, straight after it! That’s because the sample length playback settings are NOT stored in the RAM, but in the processor itself – the same reason for the “memory loss from flat batteries” issue above. The processor remembers the LAST layout recorded.

How to fix it:

You have to re-sample on an unwanted bank, the same pad length duration and pad layout as in the bank you want to keep. For example, if you want to keep the samples in bank 2, and restore them to proper playback, switch to bank 1, and record any sample, but in the same pad and length layout that you KNOW bank 2 has. It means you lose your samples on bank 1, though.

There is actually a way to preserve ALL the banks layouts, even if they’re different. You can connect a Memory Protect Switch on the chips. Plutoniq9 has created this setup for his memory expansion, which has these same issues. It involves isolating the WE (write enable) pins on each chip, and putting a toggle switch in, and toggle between the 2, with 2x 10k resistors, set up similarly in the way the CE toggle switch is set up. You can then DISABLE a chip from being overwritten. I’ve tried this, it works, but I haven’t documented it yet.

You select the bank you want to restore the sample pad layout to, switch the memory protect switch ON, and then do a false recording onto the sample pads, with the same sample length and layout for each pad, that you remember the pads really have. You press the “sample/sample long” button, you will hear the keyboard go “ding” as if it has accepted your sample, but when you play back the pad, it will have your original sample there instead, laid out correctly. Remember to switch memory protect to OFF, though, if you really intended to record new samples – you won’t record them unless you do!

Cheers, Graham

P.S. Thanks to the The electro-music.com forum group, especially mi_dach, and also Yahoo Casio SK group, especially Plutoniq9, for help in this design. You guys are legends!!!


chip pin outs.jpg
 Description:
 Filesize:  59.05 KB
 Viewed:  2549 Time(s)

chip pin outs.jpg



memory expansion wiring.jpg
 Description:
 Filesize:  114.49 KB
 Viewed:  162 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

memory expansion wiring.jpg



Last edited by gmeredith on Thu Aug 03, 2006 6:22 pm; edited 3 times in total
Back to top
View user's profile Send private message
v-un-v
Janitor
Janitor


Joined: May 16, 2005
Posts: 8932
Location: Birmingham, England, UK
Audio files: 11
G2 patch files: 1

PostPosted: Thu Aug 03, 2006 2:22 am    Post subject: Reply with quote  Mark this post and the followings unread

Hey Graham

Thanks for this!

(I've got an SK5 upstairs too)

_________________
ACHTUNG!
ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!
DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKSEN.
IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.
ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN.
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic Moderators: dnny, v-un-v
Page 1 of 1 [2 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » Circuit Bending
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use