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Subject: Re: DRAM 2MB -> DRAM 8MB
From: Andrew Jamieson (ajamiesn_at_optusnet.com.au)
Date: 2002-09-17


I'll, fix the schematics on the weekend. I connected the DRAM on them
without buzzing it out 'cos I'm a lazy bastard .... I'm more of an 8 bit
boy, which is why I made the A0/A1 error ....

You mentioned another error on the 573 part .... this suprises me, as I
would have buzzed this out ... what was the problem?

A
----- Original Message -----
From: "Matthias Wächter" <matthias_at_waechter.wiz.at>
To: <rockbox_at_cool.haxx.se>
Sent: Tuesday, September 17, 2002 9:22 PM
Subject: RE: DRAM 2MB -> DRAM 8MB

> On Mon, 16 Sep 2002, Stuart Tedford wrote:
>
> > Excellent work.
>
> Thanks!
>
> > This mod should save a lot of battery power. Could you post the results
> > when you get round to doing a test?
>
> OK, here are the first test results.
>
> 0) The hardware
>
> AJB Player 6000, updated to a 40GB IBM drive (4200 rpm).
>
> a) Modification of the firmware (using ots-rockbox-1.3)
>
> -> searching for half an hour within the various .h and .c files for the
> 2MB limitation, finally finding player.lds and modifying two lines of
> code. Looks like the correct place.
>
> b) The test data
>
> A VBR encoding of a classical piece by Anton Bruckner: Symphony Nr. 4,
> Psalm Nr. 150
>
> -> 97.1 MB (101891241 bytes) in 5 tracks and a total of 72:16/72:33/72:38
> minutes (Rockbox total/Rockbox actual/Winamp total). Total byte count
> divided by Rockbox actual tells an average bitrate of 187257 bps.
>
> c) The results
>
> -> 7.81 MB buffer free in the menu. Wow!
>
> -> The HD is spinning (red LED as indicator) at the following play times:
>
> Track 1 (18:03): 0:00- 0:07 (HD was already spinning at start)
> 5:38- 5:48
> 11:28-11:39
> 17:07-17:20
> Track 2 (15:43): 5:27- 5:37
> 11:50-12:01
> Track 3 (9:31): 1:57- 2:06
> 7:53- 8:05
> Track 4 (20:31): 4:02- 4:13
> 9:47- 9:57
> 15:24-15:35
> Track 5 (8:45): 0:51- 1:02
> 6:34- 6:46
>
> Makes a total of 13 spin-ups and a total of about 2:18 drive-up minutes.
> Not bad for nearly-192kbps material within 72 minutes, is it?
>
> d) Quality
>
> Listened to the first track, no unexpected noise, then unplugged the
> headphones and just noted the HD-on-times.
>
> > I can't wait for the details on how to do this mod. I hope it isn't too
> > hard to do, or to get the part.
>
> Well, you name it: First get the part. I got a HYUNDAI (www.hynix.com)
> part from a rare-part-reseller from Germany (www.bimex.de), packed as five
> (so I currently have four spare parts left since I didn't make it to blow
> the first part as expected :-)). I received the box at my post office
> today by paying about 64 EUR MLP (Money Leaving Pocket). The part is
> called GM71VS65163CLT5 (50 ns), and the data sheet is located at
> http://www.hynix.com/datasheet/pdf/dram/GM71V(S)65163C(CL).PDF
>
> Second is to un-solder the old part (in my case, the ISSI 2MB DRAM). We
> did this with two heating fans, set up for 400°C and directed to the pins
> of the device. About 20 seconds later, I could move the part with a small
> screw-driver and drop it on the table.
>
> After removing the chip I cleaned the solder pads with braid wire.
>
> Then I took the new part and bent two pins (A10, A11) upwards - this is
> because all other resoldering is done on previously NC (not connected)
> pins except for these two pins.
>
> I soldered the part by first mounting catercorner pins 1 and 26 and then
> soldering all other pins with _enough_ tin-solder and possibly soldering
> two or more pins together. Afterwards I used the braid wire again to take
> all the excessive tin-solder from the gaps between the pins, so that no
> pins are wrongly connected any more.
>
> After becoming aware of the schematics error of my AJB (SH1's A1 is
> connected to RAM's A0 and so on) I noted that the address pins A0-A9
> (DRAM's view) have to be connected to A1-A10 of SH1's address bus, but the
> order was unimportant, so I didn't swap the matching address pins. This
> way, only 4 address pins had to be swapped/added by additional wires. The
> other 7 wires were needed to move VCC, /WE, /RAS, VSS, /LCAS, /UCAS and
> /OE to their 'new' places. Don't expect easy soldering here - you need a
> really fine solder tip and eventually a lot of braid wire to avoid
> short-circuits. I used varnished transformer wire and used some of the
> vias on the board for easier soldering. I will post a picture of my
> AJB-crime soon - I expect a digicam for birthday... :-)
>
> After re-assembling the device I put in the batteries and - it started
> Rockbox without any additional patch or correction! Of course, the info
> menu only stated a buffer size of 1.81 MB, but there was no patch at this
> time, of course.
>
> At home I patched the firmware, updated the archos.mod via USB and started
> the device. It's like in the fairy tale, it worked at first! It showed
> 7.81 MB buffer and drastically enhanced the play time per disk spin-up. I
> don't know yet if the play time per battery charge is drastically enhanced
> but it was a lot of fun anyway!
>
> Sehr Wus,
> - Matthias
>
> --
> "To get control over people, make them trust you.
> To make people trust you
> don't try to tell them the truth about history
> but make happen what you told them about the future."
>
>
>
>



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