ROMX

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ROMX

This is a continuation of the SMD ROM Replacement for Apple ][..." thread that was started 6 months ago. What started off as a simple way to have both Applesoft and Integer BASIC ROMs in a single, switched SMD Flash chip has blossomed into a full fledged multi-bank, in-circuit programmable device with multiple fonts, instant DOS/Language Card loading and much more. More importantly, versions for the Apple IIe and Apple //c are already in the design stage.

 

So it seems appropriate to give ROMX its own thread now. And before we get too locked in on the new versions I thought it would be nice to reach out to the community for comments/suggestions for the future of this product. Currently we have 3 images for the IIe : Standard, Enhanced, and Senior PROM. As we found out previously with the first product, we know there are many others out there. Perhaps you made a custom one that others would enjoy. Please let us know what you have or what you'd like to see. Ideas can be discussed here and submissions made to Dean at theRomExchange.com. A free ROMX board to the best contribution!

 

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ROMX for the IIe

I would want to see the following ROM images:

 

-Senior PROM

-Apple-1 emulation

-DOS 3.3 auto start (ProDOS?)

-A flashable EPROM with the user's favorite application (à la Quikloader card)

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ROMX for the IIe

How would the Standard and the Enhanced configurations co-exist?
Each type comes with a different version of CPU and Character generator.

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(how do I delete my posts?, there is not a 'delete' in the edit mode....)

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I personally do not feel that

I personally do not feel that a split thread is required here. The main ROMX thread is still very much contextual. I frankly am unsure on the purpose of this second thread. 

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mi2k wrote: (how do I delete
mi2k wrote: (how do I delete my posts?, there is not a 'delete' in the edit mode....)

 That's OK. I guess you figured out that this will require a 65C02 but that both Char Gen images will be available as Text ROM banks.

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Timelord wrote:I personally
Timelord wrote:

I personally do not feel that a split thread is required here. The main ROMX thread is still very much contextual. I frankly am unsure on the purpose of this second thread. 

 

Mostly because the ROMX is no longer tied to the Apple ][,  Apple II+ and EuroPlus.

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ROMX Custom Applications
mi2k wrote:

-A flashable EPROM with the user's favorite application (à la Quikloader card)

 Almost any program that is less than 12K (15K for the ROMXe) and loads completely into RAM can be uploaded to a bank on the ROMX. It just needs some trivial loader code added to move it from Flash to RAM on boot. We do that now with several existing images. If the program uses F8 Monitor calls, subtract 2K and include that in your image.

 

Larger programs, BASIC programs, and other custom applications can also be stored in one or more banks of the ROMX but it is a little more complicated. Full details will be added to the API Guide as time permits. I'll also create an Image Template that will make this easier.

 

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ROM eX, 4X, and 5X

It's official!

ROMXe will have Michael Guidero's ROM eX image on board. Yes, the naming convention is going to be a bit confusing. His original project required giving up either the Diagnostics or Cassette routines. With ROMXe you can always switch back to the stock ROMs to use these features. Best of both worlds.

 

And our ROMXc units will ship with both ROM4X and ROM5X images as well. Thanks Michael!!

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HAPPY NEW YEAR from JD MICRO

HAPPY NEW YEAR EVERYONE!

Our resolution for 2021 is to encourage more of you to contribute images for the ROM Exchange. That’s why we put Exchange into theRomExchange.com. We know there’s lots of other images out there that the community would love to try out. And more importantly, we want to see home grown images with older programs or new creations from the programmers out there.

To that end, we’ve created a tutorial for ROMifying code and a companion disk with templates for making this extremely easy. Take your favorite small utility or game and instantly move it into ROM with three easy steps. You don’t even need a ROMX board to go through the tutorial and create images that you can run from a Language Card/16K RAM Card or with your favorite Apple II emulator. Of course, having them instantly available upon power up is what ROMX is all about. Things like our Diagnostics and Memory Tester images really prove the power of ROMX, not to forget instant loading of DOS and LC. Now we just need more options to load into our empty banks!

Go to www.theromexchange.com to download the free tutorial and .dsk image. Let’s have fun in 2021!!

Jeff and DeanJD Micro

 

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Hello Jeff, I need a reminder

Hello Jeff,

 

I need a reminder: Is the original rev of the ROMX that I have compatible with clone systems that use EPROMs, or is it only compatible with factory ][/][+ ROM boards? IDR if you added anything to autodetect this, and allow it to work with both. 

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Most of the clone boards that

Most of the clone boards that use 2716 EPROMs (e.g. those from ReActive Micro) have an inverter somewhere to correct the polarity difference in the INH line. You can use ROMX with these motherboards by bypassing the inverter, usually with a jumper inserted into the socket instead of the chip.

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Any docs on how to do this? I

Any docs on how to do this? I wish to test a clone board that usees EPROMs witht he ROMX.

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On many clones the inverter

On many clones the inverter is a 74LS02 NOR gate chip. It's almost always around E2 like on my blue Unitron board.  Your mileage may vary.

 

In general, in order to make a 9316 (or anything that's emulating a 9316) work in a 2716 socket you need to invert pins 18 and 21.  

On a 9316 pin ir is Chip Select 1 active high, and 21 is Chip Select 3 Active low, which is generally tied to pin 20, Chip select 2 active low.

On a 2716 pin 18 is Chip Select active low, and pin 21 is Vpp, the programming pin, but in general operation it needs +5V (or active high).

 

The 74LS02 inverts the required signals for chip select so that you can use 2716 EPROMS in a II+.  

So you can actually use a simple inverter chip like a 7404 on a small breadboard and an adapter socket at the D0 chip.  Just interrupt pins 18 and 21 and feed them through the inverter and then back to the ROMX.  Probably the easies way to do this is to use two stacked sockets with the appropriate pins clipped and some small jumper wires.

 

 

 

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With ROMX, the only line you

With ROMX, the only line you need to worry about is the INH signal on pin 18. In the original Apple II design this is an active low signal. That is, it will normally be high unless a peripheral card is trying to disable the ROMs. But 2716's use this pin as a chip enable so it needs to go low when accessing the ROM. On clone boards there will be an extra chip to invert this signal, as shown above by baldrick.

 

But to make ROMX work on these motherboards, the solution is not to add another inverter and more socket adapters. Just trace the signal through the extra motherboard inverter and modify that chip at its socket to bypass the inverter. You'll need to figure out which pins are involved, but the easiset way would be to bend out the pins of the IC so that those pins don't go into the socket. And add a small jumper wire instead to the socket pins that are left unplugged.

 

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I will post photos of the

I will post photos of the board when I am able. I see a 74LS00 (quad two inout NAND gate, versus 74LS02 quad two inout NOR gate), so it may be serving that function. 

 

One of the nice things on the beltron is that it has 64K as 4164s, so I would like to brin it back to life. It also has a very strange choice for the 6502: MOS C01437706. I frankly do not recall running into this variation before, but it appears to be a 6502B. I do not know why MOS would give it such an odd part number, nor is there a datasheet specific to it that I can find. The only reference to it seems to be on http://visual6502.org/ ...

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 Timelord wrote:I will post

   Timelord wrote:

I will post photos of the board when I am able. I see a 74LS00 (quad two inout NAND gate, versus 74LS02 quad two inout NOR gate), so it may be serving that function. 

 

   baldrick wrote:

   On many clones the inverter is a 74LS02 NOR gate chip. It's almost always around E2 like on my blue Unitron board.  Your mileage may vary.

 

 

For future reference, it would be nice if you can trace which pin of the chip goes to pin 18 of the ROM sockets. And if there are any other gates in the chip being used.

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jeffmazur wrote:   Timelord
jeffmazur wrote:

   Timelord wrote:

I will post photos of the board when I am able. I see a 74LS00 (quad two inout NAND gate, versus 74LS02 quad two inout NOR gate), so it may be serving that function. 

 

   baldrick wrote:

   On many clones the inverter is a 7

 

 

 

I will add it to my list. Right now, the camera on my phone does not work, so photographing this stuff is more convoluted than would ordinarily be the case. Putting a logic probe on it and tracing the pin isn't a problem, just a workbench space issue. I am disassembling some parts KBs for switches and making other Kbs functional at present. I desoldered and entire longstem today (minus the broken parts), so that should last me a while, but I have a black switch //e KB to do next. 

 

I had to fabricate a switch using a longstem switch and the plunger from a Beltron switch to use for the Beltron KB numpad-7 key. if I had thought about it more, i could have used the reset key, as it has almost the same plunger, but instead I disassembled the switch, changed it out, did continuity checks, soldered it in, and now at least I have the Beltron working, albeit with a 48K RFI mainboard. I need to get the Beltron mainboard to come back to  life at some point, but no schems means full logic probes for everything, and right now it does absolutely nothing. No beep, no video, nothing. 

 

It could just be the ROMs, which is why I am going this route first. If I had another (working) mainboard that used 4164s and ][+ style slots/KB, I would just put the Beltron board into the parts bin, and compare it to the working unit in me spare time. Alas, eople want stuid money for extremely common clones right now. Anyway, if I isolate that NAND gate 74 series chip to be the fli mechanism, I will let you know. 

 

It does not help that I need to replace my oscope. It'd frankly be nice if this was an onboard feature of a future ROMX PCB.

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   Timelord wrote:It'd

   Timelord wrote:

It'd frankly be nice if this was an onboard feature of a future ROMX PCB.

 There was a plan initially to have a jumper to set the INH polarity. But we ran out of pins on the CPLD. Since working on the //e and //c versions however, I have found some new tricks that would allow this. There is also the possibility of adding the RTC to the original ROMX for a new ROMX+. After the new boards are finished we will see if there is enough demand for this.

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Time for a quick ROMXc update
Time for a quick ROMXc update. Boards are getting ready for final beta testing. In response to a user's challenge, I've created an image to load Choplifter into one of the banks. Take a look:
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Here is another link to the

Here is a link to the facebook post which contains Jeff's  video  (it wasn't playing for me from the forum).

This is super exciting for ROMX and we're hoping that users will ROMify their favourite games/apps and share for others to install on their ROMXc/ROMXe :)

 

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ROMX does ProDOS

Work on the new ROMXc and ROMXe continues while we finish beta testing. The latest accomplishment is an image to load ProDOS into any of the banks. With a little help from Peter Ferrie (aka qkumba) we can now instantly load ProDOS or DOS 3.3 along with any System ROM as soon as the computer is turned on. And thanks to John Brooks that includes ProDOS version 2.4.2. The template will make it quite easy to build almost any version you want.

 

Currently the image loads BASIC.SYSTEM from ROM as well so you're dumped into BASIC ready to go. It will also be quite easy to have ProDOS load with a file selector or even your favorite application. And our clock driver is built into the image so as soon as you get the BASIC prompt it's ready to time stamp any files created or modified.

 

I'm also working with Peter to include ProDOS support within the firmware itself so you can load images from either DOS or ProDOS disks. Be on the lookout for a review of ROMXc from one of our favorite Apple II enthusiasts.

 

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ROMXc now in ReActiveMicro.com store!

The ROMXc for the Apple //c is now available from ReActiveMicro.

We're also posting a number of new images for this board on theRomExchange. Now it's full speed ahead on the ROMXe for the Apple //e which we hope to launch soon. Thanks again to our beta testers and others who contributed ideas for this new product.

 

 

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Review of the ROMXc

Thanks to Javier for this excellent review:

First Look at ROMXc

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JCM Review

Another nice review.

 

BTW, we have made changes to allow ROMXc to work with the ZIP CHIP. All production units are being shipped with this enhancement. Currently we just allow it to boot with the ZIP CHIP but in a future firmware update coming soon, you will be able to control the speed on a bank-by-bank basis. So set Games to run at normal speed; other software to run at full speed or somewhere in between!

 

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