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Are there new bank-switching options out there?


Propane13

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I haven't thought about this topic in a long time, so it's probably worth bringing up just to see if the lay of the land has changed at all:

 

When I worked on Get Lost, the original plan was:

  • 32K or 48K of ROM
  • POKEY or some sort of audio chip support for music.
  • some sort of save-able / battery-backed NVRAM or something (I only needed 200 bytes or so)

 

Do any emulators / hardware support the kind of options and/or configurations?

 

Also, now that POKEYS are kind of rare, what's the preferred music chip?  I saw some threads about HOKEY and Yamaha chips.  Is there an option that a lot of people are gravatating toward?

 

Finally, I seem so recall that I was hesitant to do bank-switching.  Maybe it was because I was burned out and wanted to just be done with the game, or maybe there were hardware support limitations at the time-- I frankly don't remember.  But, I have a vague recollection that without bank-switching, I had a choice between 32K + POKEY or 48K with no POKEY support due to address layouts.  I'm guessing that support for bank-switched options in emulation/hardware is pretty good these days?

 

Thank you for your time.

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4 hours ago, Propane13 said:

I'm guessing that support for bank-switched options in emulation/hardware is pretty good these days?

Yes.

 

This includes Bankset Bankswitching support under the A7800 emulator, with POKEY sound emulation (near) perfection, as of v5.2.

Hardware PCBs are utilized for the imminent mass release of Petscii Robots which saw its initial release at PRGE this year.

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You can use pokey with 48k now, but you need to use pokey@450.

 

> Also, now that POKEYS are kind of rare, what's the preferred music chip?  I saw some threads about HOKEY and Yamaha chips.  Is there an option that a lot of people are gravatating toward?

 

Hokey is basically a pokey clone. If you're looking at a cart release, pokey is where it's at, but the cart hardware will likely use hokey.

 

If you're only interested in a rom release, many DragonFly cart users have a yamaha ym2151 installed. a7800 and js7800 emulators can also do ym2151 via their XM module implementation.

 

> some sort of save-able / battery-backed NVRAM or something (I only needed 200 bytes or so)

 

There are basically two options here.

 

First, you can abuse a high-score cart entry and use that for game storage, but high-score carts are only available through emulation for the most part. Also the high score cart only gives you 25 bytes per game/difficulty, and the device only has 69 slots total.

 

Second, you can save to the AtariVox/SaveKey. There's a lot more storage available on this device. The access is through a slow serial joystick port interface, so it may take a couple frames to read/write significant amounts of data.

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19 hours ago, RevEng said:

You can use pokey with 48k now, but you need to use pokey@450.

 

Just took a look-- and wow; the last update I had recorded contained only 3 of the 16 bits populated in the a7800 header.

That's quite a lot of change.

http://7800.8bitdev.org/index.php/A78_Header_Specification

 

I'm curious why POKEY has both a $450, a $440, and an $800 option.  Seems a weird split.  Was it just different locations due to different hardware boards over time, and now $450 is kind of standard?  Just curious.

 

19 hours ago, RevEng said:

> Also, now that POKEYS are kind of rare, what's the preferred music chip?  I saw some threads about HOKEY and Yamaha chips.  Is there an option that a lot of people are gravatating toward?

 

Hokey is basically a pokey clone. If you're looking at a cart release, pokey is where it's at, but the cart hardware will likely use hokey.

 

If you're only interested in a rom release, many DragonFly cart users have a yamaha ym2151 installed. a7800 and js7800 emulators can also do ym2151 via their XM module implementation.

 

Awesome, thanks.  Glad to see that POKEY isn't as much of a potentially lost cause as it used to be.  Last I checked, HOKEY was in development (it has been a while), so if it's actually getting into carts for release, that's pretty awesome.  Hopefully, it's able to continue to be manufactured / produced fairly easily.

 

19 hours ago, RevEng said:

> some sort of save-able / battery-backed NVRAM or something (I only needed 200 bytes or so)

 

There are basically two options here.

 

First, you can abuse a high-score cart entry and use that for game storage, but high-score carts are only available through emulation for the most part. Also the high score cart only gives you 25 bytes per game/difficulty, and the device only has 69 slots total.

 

Second, you can save to the AtariVox/SaveKey. There's a lot more storage available on this device. The access is through a slow serial joystick port interface, so it may take a couple frames to read/write significant amounts of data.

 

Roger that.  I'm a bit surprised that there hasn't been a lot of interest in an independent option.  While using the add-on hardware definitely seems to be the preferred community option, has anyone ever pursued a standalone EEPROM / NVRAM?  I just think that would be an interesting feature option.  Looking at the a78 header spec, seems that the cart-type is full now, so I could see that becoming a problem (unless appended to the Save Device" field).

 

 

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2 hours ago, Propane13 said:

 

Just took a look-- and wow; the last update I had recorded contained only 3 of the 16 bits populated in the a7800 header.

That's quite a lot of change.

http://7800.8bitdev.org/index.php/A78_Header_Specification

 

I'm curious why POKEY has both a $450, a $440, and an $800 option.  Seems a weird split.  Was it just different locations due to different hardware boards over time, and now $450 is kind of standard?  Just curious.

 

 

Awesome, thanks.  Glad to see that POKEY isn't as much of a potentially lost cause as it used to be.  Last I checked, HOKEY was in development (it has been a while), so if it's actually getting into carts for release, that's pretty awesome.  Hopefully, it's able to continue to be manufactured / produced fairly easily.

 

 

Roger that.  I'm a bit surprised that there hasn't been a lot of interest in an independent option.  While using the add-on hardware definitely seems to be the preferred community option, has anyone ever pursued a standalone EEPROM / NVRAM?  I just think that would be an interesting feature option.  Looking at the a78 header spec, seems that the cart-type is full now, so I could see that becoming a problem (unless appended to the Save Device" field).

 

 

There is now an EEPROM-based cart for the 2600 with the design philosophy that existing Savekey games can be easily adapted. It’s being used for Grizzards now. I am sure the basic design ideas could be adapted to the 7800. Might need a few changes as it’s tied to 2600-style bankswitch logic but I’m sure something could work.  

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2 hours ago, Propane13 said:

While using the add-on hardware definitely seems to be the preferred community option, has anyone ever pursued a standalone EEPROM / NVRAM?  I just think that would be an interesting feature option.  Looking at the a78 header spec, seems that the cart-type is full now, so I could see that becoming a problem (unless appended to the Save Device" field).

The header is full for now, but we'll look at expanding the format at some point in the new year.

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On 12/25/2022 at 10:22 AM, Propane13 said:

Do any emulators / hardware support the kind of options and/or configurations?

On 12/25/2022 at 12:09 PM, Trebor said:

This includes Bankset Bankswitching support under the A7800 emulator, with POKEY sound emulation (near) perfection, as of v5.2.

Hardware PCBs are utilized for the imminent mass release of Petscii Robots which saw its initial release at PRGE this year.

Just wanted to add the recent update to the Atari7800_MiSTer FPGA core, release 20221227, has added Bankset Bankswitching support as well.

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On 12/26/2022 at 4:38 PM, RevEng said:

The header is full for now, but we'll look at expanding the format at some point in the new year.

when you do, I request two  things.

1. RAM at $3000-$3EFF

2. RAM at $600-$17FF

Could you make these two work? Thanks.

(If $600-$17FF is too hard to do hardware, you can just do $800-$17FF. And if $3000-$3EFF is too much, just do $300-$37FF. Thanks!)

These two would be really helpful.

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19 hours ago, llabnip said:

And... of almost no consequence... the latest A7800DS builds (Atari 7800 emulator for the DS/DSi) now supports the full Bankset Bankswitching scheme as well! 

YAYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

(unfortunately I lack a DS. :( )

Edited by Ecernosoft
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