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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: cameng on June 26, 2012, 01:15:55 AM
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Is it possible to install two extra sockets and two different kickstart roms from what is fitted into the empty spots in My A3000 marked ROM 0 and ROM 1 and swap between them?:crazy:
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What would be even cooler is to upgrade your rom space to hold twice as much stuff (Does the A3000 have 512KB Roms? I thought that's what they are). You could put a whole lot more of workbench in ROM which I think would be faster. Actually what I think would be nice is an EPROM to put AROS in, or at the very least the OS3.9 rom so that it doesn't have to be patched during the boot process.
I guess if I had one of those boards that allow blizkick or something similar...
(sigh) why is Amiga stuff so pricey?
slaapliedje
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Short answer.. NO
I believe the extra sockets were used in the A3000UX model, but I find very little information regarding this online.
Az
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Short answer.. NO
I believe the extra sockets were used in the A3000UX model, but I find very little information regarding this online.
Az
Thanks, worth a shot I guess:) Looks like I will just use my other Amiga's for compatability and install 3.1 roms and start pimping this machine, starting with my newly aquired cybervision 64. Now to raid my sisters house for my old LCD monitor!
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Short answer.. NO
I believe the extra sockets were used in the A3000UX model, but I find very little information regarding this online.
Az
I had an Amiga 3000UX and I don't remember anything in those sockets.
It was a long time ago but I'm pretty sure they were empty.
-P
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No can't use them. They weren't used in the UX.
I fairly sure I read somewhere along time ago that they were left over from prior revisions and that they were left.
Where is Dave H. when you need him?
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The other ROM positions (U182, U183) are for ICs that have a different pinout such as the 27C220 and 27C2048.
The standard positions U180, U181 are for pinouts to suit 27C100, 27C200, etc.
You can't have two types of ROMs fitted at once, although if you were to disconnect _ROMEN to each ROM pair and fit a toggle switch so that only one pair can be active at once, then it would be possible to switch between the two. You'd need to add pullup resistors on the ROM _OE lines for when nothing is connected.
But it's a lot nicer use to use a ROM switcher module or BlizKick instead of chopping the hardware around.
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It's for two different pinouts for ROMs and EPROMs.
They are wired in parallel, so which ever one has a chip in it will respond.
Edit: sniped by a better reply while I talked to my kids ;)
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No can't use them. They weren't used in the UX.
I fairly sure I read somewhere along time ago that they were left over from prior revisions and that they were left.
Where is Dave H. when you need him?
My thoughts exactly, he is probably hiding in Florida. Thanks for all your responses, I am blown away by the interlect. I might get A ROM switcher to try out. I guess the cybervision 64 will pass through or I will just swap cords.
Thunder Birds are go;)
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For most uses 3.1, the Cybervision 64 pass through, and WHDLoad make for a great system. A rom switcher makes sense if there is a game that isn't created in WHDLoad that you want to play.
Great responses from the other Amiga users.
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If you have 27C400 or equivalent ROMs in your A3000 than you already have 512KB of unused ROM capacity. The trick is in how to use it:
http://www.amiga.org/forums/showthread.php?t=59648
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What would be even cooler is to upgrade your rom space to hold twice as much stuff (Does the A3000 have 512KB Roms? I thought that's what they are). You could put a whole lot more of workbench in ROM which I think would be faster. Actually what I think would be nice is an EPROM to put AROS in, or at the very least the OS3.9 rom so that it doesn't have to be patched during the boot process.
I guess if I had one of those boards that allow blizkick or something similar...
(sigh) why is Amiga stuff so pricey?
slaapliedje
I have a set of re-programmable ROMS with a custom 3.9 ROM plus patches. Problem is compatibility eg can't boot into Workbench with no startup because the loadWB command won't work from CLI, For me this was a deal breaker, and so I took them out. I could get them re-programmed with something more compatible I suppose, but it means spending more money *sigh*
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I have a set of re-programmable ROMS with a custom 3.9 ROM plus patches. Problem is compatibility eg can't boot into Workbench with no startup because the loadWB command won't work from CLI, For me this was a deal breaker, and so I took them out. I could get them re-programmed with something more compatible I suppose, but it means spending more money *sigh*
You probably created a dependency problem when you built those 3.9 ROMs. If you look at the Remus documentation you see that some modules/libraries have dependencies on others. For starters make sure you have LoadWB in C: and 3.9 compatible workbench and icon libraries in libs:
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The other ROM positions (U182, U183) are for ICs that have a different pinout such as the 27C220 and 27C2048.
The standard positions U180, U181 are for pinouts to suit 27C100, 27C200, etc.
You can't have two types of ROMs fitted at once, although if you were to disconnect _ROMEN to each ROM pair and fit a toggle switch so that only one pair can be active at once, then it would be possible to switch between the two. You'd need to add pullup resistors on the ROM _OE lines for when nothing is connected.
But it's a lot nicer use to use a ROM switcher module or BlizKick instead of chopping the hardware around.
Are you sure about the type of roms the 2 sockets can use? I know the 27c220,2048 etc can replace the rom tower(which used 27c200,400 etc) on the rev 7 boards direct(u180,181) eliminating it ,but i seem to recall i tried the 27c220/2048 etc in the u182,u183 positions and it did not work. My memory may be failing me but those sockets don't seem to work for any rom/eprom pinouts i found.
Have you actually used those sockets?
Mech
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I think those sockets are inverted, that's why the rom towers were originally needed.
If I remember right, you need to fold all the pins the wrong way so that the chip is upside down in the socket.
I'm not sure if they ever fixed it or just started using the other two sockets.
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Are you sure about the type of roms the 2 sockets can use? I know the 27c220,2048 etc can replace the rom tower(which used 27c200,400 etc) on the rev 7 boards direct(u180,181) eliminating it ,but i seem to recall i tried the 27c220/2048 etc in the u182,u183 positions and it did not work. My memory may be failing me but those sockets don't seem to work for any rom/eprom pinouts i found.
Have you actually used those sockets?
All of my hardware development work was based on the U180, U181 positions so I've not personally used the U182, U183 positions.
I've seen various examples (http://amiga-hardware.com/download_photos/a3000rev61mb_1_big.jpg) of A3000s with 27C220 ROMs in U182, U183 so I would assume they work on at least some PCB revisions.
If you're having issues, then compare the pin detail from the EPROM datasheet to what's presented on the A3000 hardware.
A potential trap for hardware newbies is that the high order address line(s) such as A17 (pin 1) is floating on certain revisions of the A3000D main board, including rev 8.9 and possibly earlier ones. Was fixed (tied to ground) in rev 9/03.
The result is that if you're using EPROMs larger than 256kB x 16 (4Mbit) then the high order address line floats and may cause unpredictable results. I know some memory devices refuse to work correctly at all if any of the address lines are floating, even if the data image is mirrored to both halves of the address range.
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My 3000 has these special ROMs in it, ordered from Software Hut back in 2000 to replace my lame rom tower.
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All of my hardware development work was based on the U180, U181 positions so I've not personally used the U182, U183 positions.
I've seen various examples (http://amiga-hardware.com/download_photos/a3000rev61mb_1_big.jpg) of A3000s with 27C220 ROMs in U182, U183 so I would assume they work on at least some PCB revisions.
If you're having issues, then compare the pin detail from the EPROM datasheet to what's presented on the A3000 hardware.
A potential trap for hardware newbies is that the high order address line(s) such as A17 (pin 1) is floating on certain revisions of the A3000D main board, including rev 8.9 and possibly earlier ones. Was fixed (tied to ground) in rev 9/03.
The result is that if you're using EPROMs larger than 256kB x 16 (4Mbit) then the high order address line floats and may cause unpredictable results. I know some memory devices refuse to work correctly at all if any of the address lines are floating, even if the data image is mirrored to both halves of the address range.
Good info there, it may of been a case of bigger eproms and the floating aqddress line.I was testing on a old rev7 at the time i believe. i had sworn it worked but originally i may of tested on a 9/02.
thanks for the info.
mech
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Good info there, it may of been a case of bigger eproms and the floating aqddress line.I was testing on a old rev7 at the time i believe. i had sworn it worked but originally i may of tested on a 9/02.
thanks for the info.
mech
I purchased a pair of 3.1 ROM's which were in fact 27C400s. I also have the rev. 8.9 mobo which leaves pin 1 of the ROMs floating. I Never had a bit of trouble with them even when the mobo was over-clocked and ROM timing was set for the fastest speed. They had a mirror image burned into the upper and lower 256KB of each ROM so they would have worked with pin 1 to GND or VCC although left floating is usually resolved as a logical high by the internal address buffers.
I also have a pair of TC574200 which I burned a 512KB 3.9 ROM image into using the mirror method which worked fine with pin 1 floating also. It wasn't until I did the 1MB ROM hack that I finally got around to connecting pin 1 to A19! But that's just my personal experience. :razz:
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I purchased a pair of 3.1 ROM's which were in fact 27C400s. I also have the rev. 8.9 mobo which leaves pin 1 of the ROMs floating. I Never had a bit of trouble with them even when the mobo was over-clocked and ROM timing was set for the fastest speed. They had a mirror image burned into the upper and lower 256KB of each ROM so they would have worked with pin 1 to GND or VCC although left floating is usually resolved as a logical high by the internal address buffers.
Of course it depends on the device being used. Older UV EPROMs tend to be quite forgiving in terms of floating address lines. As you say, some of these devices have internal pullups on the address lines so you can get away with leaving these inputs floating. But again, that can vary between manufacturers.
Many modern flash based devices aren't as tolerant. I found some of these were totally unreadable over the entire address range when a high order address line was floating. That's how I first came across the floating address lines in the earlier A3000s.
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Simple answer: yes and no. No, don't use the other sockets. Yes you can add and boot from different ROMs by piggy-backing them on top of each other, using a switch, a 22k ohm resister for each ROM to "pull low" the selected ROM, and a full pin schematic of the ROM. I can't tell you which pins for Amiga ROMs while typing in bed on my iPhone at 4:57 am on a Sunday morning, but I've done it on my two C128D's and an Osbourne CP/M computer. Just Google "piggy-Back ROMs" to find out the why and how and compare the Vcc pin & Ground pin on the Amiga's ROM
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Awesome info. I hav'nt dabbled with electronics for a while and its been a long time since Amiga was my second language. I shall give it a go at some stage. FYI my moby is a rev 9/03 and I also have a C128D, which I am having trouble booting, but a topic for another thread :)