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New Harmony product: Harmony Encore


batari

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Depending on how clumsy or unlucky you are, the microSD falls inside the flash cart much more frequently than the SD card. ;)

SD cards are tiny enough as it is. Why shrink the tech even more? If you need a micro SD card, just use an adapter. Many of them come with one by default. Also LOL on losing your card inside the Harmony. Reminds me of when I was learning guitar and I would ever so often drop my pick inside.

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Any estimate on when the Deluxe editions will be available to purchase/pre-order?

http://atariage.com/forums/topic/220696-new-harmony-product-harmony-encore/page-13?do=findComment&comment=3101201

 

"I could produce a Deluxe edition, but I would prefer to wait until I can put some Encore-only game demos or homebrews on the SD. Since I obtain permission for all homebrews I have on the SD, this may take some time."

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There is a bug in some of the DPC+ games out there that is only now being exploited by Encore hardware. It was fixed years ago, well before Encore was conceived, but apparently there are more games out there still using the old code with the bug. I thought it only affected bB games, but it sounds like Space Rocks may have the old code as well.

 

If you have any DPC+ games that don't work, please post them here and I can provide fixed versions that do work on Encore.

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Some of my previous downloads don't seem to work. Space Rocks for one. I redownloaded it and it still doesn't work.

There is a bug in some of the DPC+ games out there that is only now being exploited by Encore hardware. It was fixed years ago, well before Encore was conceived, but apparently there are more games out there still using the old code with the bug. I thought it only affected bB games, but it sounds like Space Rocks may have the old code as well.

 

If you have any DPC+ games that don't work, please post them here and I can provide fixed versions that do work on Encore.

Well then, the Encore simply isn't 100% backwards compatible then! Will these "fixed" versions also not work on the original Harmony? :dunce:

Edited by stardust4ever
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There is a bug in some of the DPC+ games out there that is only now being exploited by Encore hardware. It was fixed years ago, well before Encore was conceived, but apparently there are more games out there still using the old code with the bug. I thought it only affected bB games, but it sounds like Space Rocks may have the old code as well.

 

If you have any DPC+ games that don't work, please post them here and I can provide fixed versions that do work on Encore.

Yes, the fixed programs will work on the original Harmony.

It is just the ARM code that emulates the DPC+ chip. (Not that a physical DPC+ chip ever existed. Kind of blows your mind, no?)

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There is a bug in some of the DPC+ games out there that is only now being exploited by Encore hardware. It was fixed years ago, well before Encore was conceived, but apparently there are more games out there still using the old code with the bug. I thought it only affected bB games, but it sounds like Space Rocks may have the old code as well.

 

If you have any DPC+ games that don't work, please post them here and I can provide fixed versions that do work on Encore.

Add Frantic and QbBertari WIP's to the list. I don't know what is DPC+ and what isn't, but these don't seem to work either..

Edited by roryjr
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Yes, the fixed programs will work on the original Harmony.

It is just the ARM code that emulates the DPC+ chip. (Not that a physical DPC+ chip ever existed. Kind of blows your mind, no?)

I'm guessing the original DPC+ code used undocumented opcodes the old ARM supported, but not the new ARM?

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Well then, the Encore simply isn't 100% backwards compatible then! Will these "fixed" versions also not work on the original Harmony? :dunce:

The games can work. It's the bug that's not supported (and this bug shouldn't be "supported" - I will explain why.) Fixed versions will work on any Harmony. I wouldn't say it's not backward compatible. I will fix the games so they will work because I think people just want to play the games. But the bug could also be worked around with a BIOS update. That will take more time though.

 

There's no point in speculating the source of the bug so I'll explain where it comes from and why some hardware does not exploit it.

 

The first 50 Harmony carts sometimes would enter in-system programming mode during boot (5% of the time, maybe) so to fix this, I added a MOSFET and other parts to isolate the signal that was causing the issue until the cart was up and running. Once going, the BIOS could turn on the MOSFET and all would work normally. Harmony Encore uses an analog switch instead of a MOSFET to do the same task. If code is correct, it should not make a difference what sort of isolation method we use.

 

The bug in DPC+ was that the MOSFET or analog switch was accidentally turned off when it's not supposed to be. These DPC+ games turn the device off very briefly, and accidentally, at just the wrong time (when trying to pull out of the spinner screen.) The only reason that original Harmony carts work is because a MOSFET has a body diode that will still conduct on one direction even when it's off, causing the bug to not be exploited by regular Harmony carts but get exploited by Encore.

 

Now here's the thing: In my engineering opinion, no device should ever rely on the MOSFET body diode effect. BIOS images before 1.03 are contraindicated on Harmony because they have no code to handle the MOSFET. The body diode is not an intentional feature but instead a side-effect of the manufacturing process of MOSFETs, so they weren't designed to handle being used in this way. But, don't worry about these DPC+ games with a bug on your Harmony - the possibility of damage from a DPC+ game is one in a million as they use the body diode just one time. However, if you loaded a pre-1.03 BIOS and tried to use it, it would cycle the body diode a half-million times a second. Even that probably wouldn't damage it unless you left your cart on overnight or something (but, these old BIOSes probably wouldn't work anyway, so nobody's going to do that.)

 

Now the reason the bug stuck around is because there was no way to know if it was "fixed" because it was not exploited. So I think the fact that it's being exploited now is a good thing because now I'm aware that it's still out there and I can work around it.

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The games can work. It's the bug that's not supported (and this bug shouldn't be "supported" - I will explain why.) Fixed versions will work on any Harmony. I wouldn't say it's not backward compatible. I will fix the games so they will work because I think people just want to play the games. But the bug could also be worked around with a BIOS update. That will take more time though.

 

There's no point in speculating the source of the bug so I'll explain where it comes from and why some hardware does not exploit it.

 

The first 50 Harmony carts sometimes would enter in-system programming mode during boot (5% of the time, maybe) so to fix this, I added a MOSFET and other parts to isolate the signal that was causing the issue until the cart was up and running. Once going, the BIOS could turn on the MOSFET and all would work normally. Harmony Encore uses an analog switch instead of a MOSFET to do the same task. If code is correct, it should not make a difference what sort of isolation method we use.

 

The bug in DPC+ was that the MOSFET or analog switch was accidentally turned off when it's not supposed to be. These DPC+ games turn the device off very briefly, and accidentally, at just the wrong time (when trying to pull out of the spinner screen.) The only reason that original Harmony carts work is because a MOSFET has a body diode that will still conduct on one direction even when it's off, causing the bug to not be exploited by regular Harmony carts but get exploited by Encore.

 

Now here's the thing: In my engineering opinion, no device should ever rely on the MOSFET body diode effect. BIOS images before 1.03 are contraindicated on Harmony because they have no code to handle the MOSFET. The body diode is not an intentional feature but instead a side-effect of the manufacturing process of MOSFETs, so they weren't designed to handle being used in this way. But, don't worry about these DPC+ games with a bug on your Harmony - the possibility of damage from a DPC+ game is one in a million as they use the body diode just one time. However, if you loaded a pre-1.03 BIOS and tried to use it, it would cycle the body diode a half-million times a second. Even that probably wouldn't damage it unless you left your cart on overnight or something (but, these old BIOSes probably wouldn't work anyway, so nobody's going to do that.)

 

Now the reason the bug stuck around is because there was no way to know if it was "fixed" because it was not exploited. So I think the fact that it's being exploited now is a good thing because now I'm aware that it's still out there and I can work around it.

Interesting. I know NPN or PNP bipolar can be used as diodes as well. Quick question, my understanding of MOSFETs is that they are are built similar to a bipolar but with a thin insulator is on the collector. When a charge appears on the collector, the opposite charge appears inside the transistor. This momentarily changes the doping type on the center layer of silicone, allowing current to pass between base and emitter. My question is how can a MOSFET function as a diode if the collector gate is isolated? This would prohibit any current to flow across the collector beyond that allowed by the tiny capacitance.

 

Back on topic, is there a list of game ROMs that are affected by the bug?

Edited by stardust4ever
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MOSFETs have more layers of silicon than an NPN. I think four N layers and two P layers? So what happens is that with all those layers, it can act as a parasitic NPN. So to stop that internal NPN from saturating and messing things up, they essentially connect drain to body to turn that NPN into a diode. We didn't really want the diode either but it's a less-bad solution. But anyway, the body diode is conducting which hides the bug.

 

But anyway, I think the list is going to be limited to these DPC+ games. I can fix all of them easily (the problem is just a single instruction.)

 

To fix any errant DPC+ games, use a hex editor to change the bytes at offset 0x200 from 00 A0 85 to 01 A0 C5. Then they will load on Encore (or any other Harmony version) with no problem.

 

I will work on a new BIOS, which will check to see if you're trying to run an old DPC+ version and make the above patch to its own internal memory when the game is run. Shouldn't be too hard to do.

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MOSFETs have more layers of silicon than an NPN. I think four N layers and two P layers? So what happens is that with all those layers, it can act as a parasitic NPN. So to stop that internal NPN from saturating and messing things up, they essentially connect drain to body to turn that NPN into a diode. We didn't really want the diode either but it's a less-bad solution. But anyway, the body diode is conducting which hides the bug.

 

But anyway, I think the list is going to be limited to these DPC+ games. I can fix all of them easily (the problem is just a single instruction.)

 

To fix any errant DPC+ games, use a hex editor to change the bytes at offset 0x200 from 00 A0 85 to 01 A0 C5. Then they will load on Encore (or any other Harmony version) with no problem.

 

I will work on a new BIOS, which will check to see if you're trying to run an old DPC+ version and make the above patch to its own internal memory when the game is run. Shouldn't be too hard to do.

That sounds awesome if you get that patch in. So the DPC+ code is always in the same place? I thought code could arbitrarily be placed anywhere within the ROM.

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Some research indicates there are at least two old DPC+ versions out there. I have created a BIOS update that handles these two known variants. Please test on all DPC+ games you have, and if any don't work, please let me know so those can be handled as well.

 

To update BIOS: copy the two files to the root directory of your SD card. Make sure no other files starting with "hbios" exist on your card other than the one provided in the attached zip file, then insert the card in your Harmony and select the "BIOS_updater.cu" and it will update your BIOS.

Harmony_bios_106_beta5.zip

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Some research indicates there are at least two old DPC+ versions out there. I have created a BIOS update that handles these two known variants. Please test on all DPC+ games you have, and if any don't work, please let me know so those can be handled as well.

 

To update BIOS: copy the two files to the root directory of your SD card. Make sure no other files starting with "hbios" exist on your card other than the one provided in the attached zip file, then insert the card in your Harmony and select the "BIOS_updater.cu" and it will update your BIOS.

Is this file compatable with older Harmony carts?

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  • 1 month later...

I don't see why we need a separate subdomain for Harmony. It only causes confusion and possibly resulted in a few missed sales over the years.

 

Harmony could be offered on the main site even if it's run by another guy. Shipping for Harmony would be a separate charge and store orders containing Harmony as well as other items could be split.

 

At the very least, the Atartiage store needs a placeholder page for Harmony products with a link to harmony.atariage.com :ponder:

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