Since 2024 the hardware of the MEGA65's Expansion Port (aka cartridge port) is now 100% compatible to the C64's hardware as it has bi-directional signals for RESET, IRQ and NMI. Even though the current version 5.1 of the C64 core is "only" supporting bi-directional RESET and not yet supporting bi-directional IRQ/NMI, this already leads to a great leap forward in compatibility with all sorts of cartridges which are now "just working".
Older hardware revisions of the MEGA65 are not as compatible. So if you have a machine that was built before 2024, then please make sure you understand the restrictions and/or apply the workarounds described in this document.
Learn more about different MEGA65 revisions here.
Some modern "homebrew" cartridges come as a raw PCB, without a plastic case. Never insert a raw PCB into your MEGA65's Expansion Port. It is nearly impossible to align all the pads and connections correctly so you might damage the MEGA65 - or - in less drastic cases the cartridge will not work reliably, but "only sometimes" and you will experience strange bugs.
Put your cartridges in cartride cases from The Future was 8BIT or from Protoparts.
First of all: Please support our friends at Protovision and RGCD and buy as many original hardware cartridges from them as you can and want to afford. The Commodore 64 community needs to stay alive and therefore publishers who are publishing to our beloved computer more than 40 years after its release should be rewarded.
But there are many awesome game releases and other releases on csdb.dk that are not published on a hardware cartridge. And unfortunately more often than not, your favorite cartridge is sold-out on Protovision and RGCD.
So you might need another solution.
Why would you want to use real hardware Flash Cartridges on the MEGA65
while the MEGA65 can simulate cartridges using *.crt files that you can
store on and load from your SD card? The answer is, that a simulation is never
as perfect as real hardware: We use the MEGA65's HyperRAM to store the data
from the *.crt files when we simulate the cartridge. While this works very
well in more than 99% of the cases, the constraints of the HyperRAM (for
example its latency) can lead to undesired artefacts when playing simulated
cartridges: We actually need to halt the CPU for a short period of time, each
time the cartridge does a bank switch. Most of the time you won't notice, but
as said, there can be unintended consequences.
So for a 100% glitch-free retro experience, you might want to use real hardware, i.e. real Flash Cartridges.
The original EasyFlash (aka EasyFlash 1) and the cost reduced EasyFlash 1CR are for sure among the most popular cartridges in the scene. Many new games and other releases come in the EasyFlash cartridge format. Here is a description about the EasyFlash taken from the original EasyFlash website:
"EasyFlash is a cartridge for the C64 expansion port. In contrast to traditional cartridges, this one can be programmed directly from the C64.
You can easily create various classic computer game cartridges or program
collections with it. All what you need to do this is a C64, an EasyFlash,
the software available
here
and an image of the cartridge *.crt. As these *.crt files may be
quite large, a large capacity disk drive like the
FD-2000 or an
SD2IEC
device may be useful. For smaller drives EasySplit can be used to compress
and split large cartridge images."
Learn more about the EasyFlash on the C64 Wiki.
Using the our C64 core, your MEGA65 is able to flash EasyFlash cartridges.
Since the original EasyFlash 1 is hard to find these days, we will focus on the EasyFlash 1CR by Daniël Mantione. This handy cartridge is officially and proactively supported by the C64 for MEGA65 core development team, so this is your number one go to Flash Cartridge. Buy it here by filling out Daniël's form. Scroll down to the bottom of his web page to find an order form. Here are some important considerations:
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Use the field where you specify your postal address to add the comment that you want a so called "Through Hole" version of the cartridge and not the so called "SMD" version of the cartridge. Only the "Through Hole" version is supported on the MEGA65 at this time. (This might change in future.)
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We highly recommend that you buy fully assembled cartridges to ensure that they actually work in your MEGA65.
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You need a case for the cartridge. The easiest way to obtain one is to order it from Daniël's website together with your Easy Flash 1CR.
The following image shows, how the "Through Hole" version of the EF 1CR looks like and it shows different case variants that Daniël sells. We recommend to order a The Future was 8BIT or Protoparts. case.
As "CR" stands for "cost reduced", one of the basic idea of the Easy Flash 1CR is that it is affordable enough to be the Flash Cartrdige for all the cartridge-based games that you really love: Flash once and enjoy forever. Buy one cartridge per game. For avoiding misunderstanding: The EF 1CR can be re-flashed as often as you like.
Conveniently, the Easy Flash 1CR comes with a preinstalled flasher: When you
insert the cartridge into your MEGA65's Expansion Port and start the machine
then you will see the EasyFlash program's start screen and you will
imediatelly be able to flash the *.crt file as
described here. If you don't have a
SD2IEC
or something similar, then you will likely need to split large *.crt files
into multiple *.d64 images using
EasySplit. Watch this
YouTube video
to learn how the flashing on the MEGA65 works when you have split the *.crt
files into multiple *.d64 files.
After you flashed the EF 1CR for the first time, the built-in flasher is gone and replaced by the game you flashed. If you want to re-flash at a later stage you need to either use a screwdriver, open the case, move the switch to the PROG position, close the case again, start the MEGA65 while the cartridge is inserted, re-flash using preferably this version of EasyProg, open the cartridge case with a screwdriver again, move the switch back to the BOOT position, close the case again and you are good to go. CAUTION: Do not fall for the temptation to not use the plastic case! See above, very first headline of this file.
As this is obviously a onerous workflow, we recommend that you cut or drill some holes into the EF 1CR's case. Here are two examples from the MEGA65 team:
| Lydon's Example | sy2002's Example |
|---|---|
 |
 |
This version of EasyProg is from the creator of the EF 1CR and is recommended for re-flashing the EF 1CR. You can also use EasyProg 1.8.1 or newer.
The EasyFlash 3 (EF3) is quite a beast: It sports seven 1 MB slots for game and application cartridges. Each of these slots represents a full-featured EF1 cartridge. Additionally it can replace the internal Kernal with one of up to eight Kernals saved in the cartridge. The EF3 can also run freezer cartridge images such as Action Replay, Retro Replay, Nordic Power / Atomic Power and Super Snapshot 5. Learn more here.
IMPORTANT: The C64 for MEGA65 core is not yet supporting all features of the EF3, so read the following information carefully.
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Insert the EF3 into the Expansion Port and turn on your MEGA65. You will see the EF3's menu.
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Press K while you are in the EF3's menu to kill the cartridge and go back to the C64's BASIC.
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Return back to the EF3's menu any time by pressing the MEGA65's Reset button.
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Flash up to seven 1 MB standard slots and up to two Freezer slots using the built-in flasher (optionally also in conjunction with large IEC storage devices such as the SD2IEC). To do so, press P while you are in the EF3's start menu to start EasyProg. You can flash multiple slots (one after the other) while EasyProg is running. Make sure that you enter meaningful names for the slots when being prompted by EasyProg.
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Play games by pressing a letter between A and F or start freezers by pressing R, Y or S.
Instead of using the keys mentioned above, you can also navigate the menu using a joystick in port #2 or by using the cursor keys and Return. Press Space to switch back and forth between the different pages of the EF3's main menu.
When you run a clean/unmodified EF3 for the first time, then the Action Replay is in the slot that you can start with the Y from the EF3 menu.
The Special button of the EF3 works as the "freeze" button of the selected freezer cartridge.
The following freezers are working. Download their binaries from
rr.pokefinder.org as these binaries are known
to work. Always make sure that you flash the *.bin
version of the freezer:
The Retro Replay is not working, yet.
Use the built in flasher that you can start with P from the EF3 menu to flash freezers.
If you have a MEGA65 that was built in 2024 or later, all buttons are working as expected. Otherwise you can expect the behavior as described here.
The EF3's Reset button does not work at all. The reason is that the MEGA65's R3 and R3A board's electronic cannot sense the reset signal of any cartridge inserted into the Expansion Port.
The Menu button does not work, yet for unknown reasons. But this is not really a problem: Just press the MEGA65's Reset button to return back to the EF3 menu.
The Special button works as intended as "freeze" button if you are running a freezer cartridge. But it does not bring you back to BASIC ("Kill the cartridge") when you pressed it while you are in the EF3 menu. Use the key K instead to go back to BASIC.
We are deliberately not supporting the Kernal mode of the EF3, because in Kernal mode, the EF3 manipulates the address line A14, meaning it pulls at this address line while the C64 core might simultaneously be doing the opposite. The way how the MEGA65's hardware is built leads to a clash in such a situation which might either harm the MEGA65 or the EF3.
For making sure that you're always on the safe side when using the EF3, we deactivated the Kernal mode. You will notice that the border of your screen is flickering if you try to enter the Kernal mode. This is the safe state, nothing bad happens here. Just press Reset to try something else.
We are not yet supporting the Kernal mode of the EF3 in Version 5.1, but we plan to support it in a future release of the C64 for MEGA65 core.
Kung Fu Flash (KFF) can emulate different cartridge types, load PRG files and use D64 disk images. Just place your desired CRT, PRG or D64 files on a FAT formatted microSD card and use the built-in launcher to execute them.
Kung Fu Flash is a so called Software Defined Cartridge where a fast microcontroller emulates cartridge hardware in software. This makes it extremely flexible, allowing different cartridge types to be supported at a relatively low cost. However, it can be challenging to get the C64 bus timing correct in software and in some places the timing is very close to the limit.
You might sometimes experience glitches when running demanding software, so in general it is fair to say the EF1 or the EF3 are more compatible with the C64 for MEGA65.
But it is also important to mention that KFF induced glitches seem to be very rare: We tested very demanding games with the KFF such as "Eye of the Beholder", "A Pig Quest" and "Prince of Persia" and none of these games showed any glitches. Overall, the KFF works great with the C64 for MEGA65.
If you have a MEGA65 that was built in 2024 or later, the Kung Fu Flash will "just work". You can ignore this section. If you have an older machine, then read on to learn how to use the KFF.
The circuits of the MEGA65's R3 and R3A boards are not able to detect the KFF's signals properly. Therefore you need a workaround to work with the KFF. It takes a bit of practice to get the timing right, but as soon as you are getting the hang of it, you can work very well with the KFF and the C64 for MEGA65 core:
Always press the KFF's buttons in parallel with the MEGA65's Reset button.
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To enter the KFF's menu, press MEGA65 Reset plus KFF Menu. From here you can flash cartriges, programs or tape images to the KFF.
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To start a game, press MEGA65 Reset plus KFF Special.
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After you loaded a cartridge, program or tape in step (1), you need to explicitly perform step (2) - autostart does not work.
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When you switch on your MEGA65 while the KFF is inserted into the Expansion Port, then the system initially crashes. Don't worry, this is "normal". Now decide whether you want to enter the menu, then perform step (1) or if you want to start the game, then perform step (2).
If you have a MEGA65 that was built in 2024 or later, all buttons are working as expected. Otherwise you can expect the behavior as described here.
The KFF's Reset button does not work at all. The reason is that the MEGA65's R3 and R3A board's electronic cannot sense the reset signal of any cartridge inserted into the Expansion Port.
The other two buttons Special and Menu work in the context described above in "How to use" but they do otherwise not work as intended.
If you have a MEGA65 that was built in 2024 or later, then freezer most cartridges are supposed to be working as expected. Due to the fact that we did not implement bi-directional NMI and IRQ lines, yet in Version 5.1 of the core, there might be freezer cartridges that are not yet working as expected, even on a 2024 MEGA65. We plan to continue to improve the core to support more freezer cartridges on the KFF in future.
Otherwise, if you have a pre-2024 MEGA65, due to the Special button not working as expected, you cannot activate the "freeze" menu of freezer cartridges.
- Action Replay
- Epyx Fast Load
- Final Cartridge III (with workarounds)
- GeoRAM
- PowerCartridge
- Super Snapshot
When you insert a Final Cartridge III into the MEGA65's Expansion Port and switch-on the machine then you will encounter one of two situations instead of beeing greeted with the FCIII's main menu:
- You will land in BASIC
- You will see a "blue screen", i.e. the standard C64 background and frame color but without anything readable or garbage on it
To start the Final Cartridge you need to perform the following three workaround steps one or multiple times in a row:
- Press the Reset button of the FCIII
- Wait one second
- Press the Reset button of the MEGA65
As soon as the FCIII started properly, mostly everything works fine, including
the fast loader and the Freezer button (at least most of the time).
But not everything within the freezer menu works as intended. For example when
exiting the machine language monitor with x, the C64 does not continue
where it left off.
If you have a MEGA65 that was built in 2024 or later, reset buttons are supposed to work as expdected.
Otherwise, the reset button will not work. The reason is that the MEGA65's R3 and R3A board's electronic cannot sense the reset signal of any cartridge inserted into the Expansion Port.
GeoRAM works. Make sure that you use a GEOS boot disk with support for GeoRAM. Here are two locations where you can download such boot disks: