GBA1000 rev4 Build Log

I don't suppose anyone could confirm which memory bank is related to which fast ram chips could they? I have problems with $40000 - $5FFFF (or $140000 etc. in 32bit mode). When I ran some loop tests on that area the chip select lines suggested it was IC62 to IC65 but that didn't strike me as being right looking at the schematics. Or I was just getting a bit confused!

Thanks.
 
I just realised, all the LS-14250 batteries I can find are non-rechargeable... so now I am wondering, looking at the schematic, it has a diode in front of it (BAS23L), so maybe it does not charge? in that case a non-rechargeable LS-14250 is ok...
 
Hmm, interesting question now that I looked more closely. The schematics show a 1k resistor in parallel with the diode, which could allow a small current to go through, probably only in the range of a milliamp or two. Someone would need to look more closely into the circuit but I think it's not really intended to be charged, and that's why the type of the battery is a special long-lasting one.
 
ajk said:
1200 mAh doesn't refer to current, but capacity. The clock chip actually uses current in the range of micro-amperes (µA) :) The suggested LS14250 is a certain type of very high-capacity lithium battery that should last a long time.
Click to expand...

Oh man, that's right :) thanks for clarifying that up.
 
i modded my jtag with a 74hc244 to programm the lsi1024 with info from french site, now work at 40mhz (at 50 don't start), i loaded the workbench from floppy and 2 megachip ram are displayed
 
problem with ide, led activity on, i need more info on eprom and gal
 
??? i have insert a zorro2 AT-Bus 2008 with a cf with wb, the cf boot and work fine and display 8 mega of fast ram ???

without zorro2 card the fast ram is zero
 
I'll hopefully get the few remaining parts this week so I can try to boot my board and see what happens.
 
I have tried my board yesterday evening.

- First test without HD. The kickstart screen appears! Good!:)
So I have reboot with a floppy game. Run fine! video & sound are OK. Joystick also!:)

- Second test with HD. I have connected a CF card with WB3.1. The system is launched normally!:)

At this time, the flicker fixer is tested and the battery for the clock isn't connected.

Memory found:
- CHIP : 2M.:)
- FAST: 0M.:sad:

Pfffff... I have to check this part. I'm a little bit disappointed.
 
BloodyCactus said:
did you run the gba1k config tool to setup the memory properly?
Click to expand...

I must admit that no.
I understood that at the first boot, FAST memory is seen as 24-bit memory, and then had to run the utility to switch to 32 bit.
I make mistake?! It's normal if I find 0M of Fast-RAM?

And what must be the configuration of the two jumpers S5 & S6 when I use GBA1K config?
 
Last edited:
1- I redid the solders of the SRams. Nothing change. Always 0M of FAST Ram.

2- I tried to active the FAST Ram manually with addmem $0200000 $09FFFFF. Always 0M of FAST Ram.
So, there is a real problem onto the FAST Ram part.

3- Under SYSINFO, only CHIP RAM found... logic.:mad:
But an another problem is shown after a speed test... My GBA run at 13,40 MHz... with a 100MHz Oscillator, and R135 in place (33R2).

I have put the resistor onto R122 with a 50MHz oscillator. And the frequency is always 13,40 MHz.:censored::banghead:

If someone has an idea, I'm interested...
 
Last edited:
@Tuxbar

Regarding the frequency, have you got the chip on the bottom side too, IC78?
 
ajk said:
@Tuxbar

Regarding the frequency, have you got the chip on the bottom side too, IC78?
Click to expand...

Yes, IC78 is onto its place. This is what I don't understand. With R135, the signal passes through IC78.
And with R122, the signal is direct from the oscillator. IC78 is by-passed in the case.

In the two cases, the frequency is always the same. Strange no? I have a 68030 which runs at the same speed as a 68000...
 
Last edited:
Finally finished mine off today, the parts were originally bought from fitzsteve as he decided not to go ahead with the build. It's been running for a couple of months now but I had the battery / holder to fit and to figure something out with the LEDs.

a5yre8e7.jpg


I looked at using a bi-colour LED but couldn't find any 7mm ones with common anode. I did find some 7mm x 2mm bi-colour when reversed but decided it was going to be a real faff to make that idea work. In the end I used those LEDs but not in bi colour mode and added an extra LED for the HDD. Plus side is I can change the colour of each one by turning the cable around to the mainboard.

umaqe4u5.jpg


I'd like to build George Brauns ram expansion and possibly something to add networking next!



Sent from my iPhone using Tapatalk
 
Hi,
also building BGA1k but I'm still few IC away from the end plus with probably impossable task of soldering TSOP ahead of me :(
One question to Ordyne: what are those board you used in place of IC21 and IC25? During desoldering originals from A500 I broke one and have no replacement... :Doh:
 
Kipper made up some hybrid boards, IIRR they were available complete or in kit form.


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