Classic / Mega Everdrive

tryphon · Post by **tryphon** » Mon Sep 22, 2014 7:39 am

Hi,

I've just purchased a good ol' Megadrive from ebay and I'm willing to acquire an Everdrive (I make hacks and fan translation, and I intend to code homebrews - or at least quite deep hacks).

There's quite a difference of cost between both, and I was wondering :

What can make me willing a Mega Everdrive rather than a classic one ? Which features of the former are really useful ?

MintyTheCat · Post by **MintyTheCat** » Mon Sep 22, 2014 10:17 am

Consider using UMDK for development work:

viewtopic.php?t=1825

I have both the Everdrives for the MD and a UMDK and I can tell you that UMDK is substantially better for development work. It can be used as a standard Flash Cart too.

tryphon · Post by **tryphon** » Tue Sep 23, 2014 8:37 pm

I understand this is worth considering (I've already read this thread more than once) but :

1) I'm used to emulators. I know UMDK offers uncomparable possibilities for debugging, but I'm from old school, I don't even use a debugger when I code in C or python

2) I don't know how much an UMDK would be (I saw 80 € in the thread but it wasn't confirmed)

3) I don't know how long it would take to get one (I didn't totally understand the aim of the thread).

I think UMDK is a little overpowered for my use, so unless its price speaks in its favour, I don't see the point to have one. But I may be wrong and am ready to change my mind

Post by **KanedaFr** » Thu Sep 25, 2014 11:56 am

If I compare the 2 models, it seems the mega everdrive is the best one.

1/ more memory
2/ CD bios and ram feature
3/ firmware update
4/ usb feaure

http://krikzz.com/index.php?route=produ ... duct_id=50
http://krikzz.com/index.php?route=produ ... duct_id=55

I hope you have now all the info to make your choice between the 3 possibilities

elusive · Post by **elusive** » Wed Oct 08, 2014 8:48 pm

I had both versions of the Everdrive, and if you're into playing Sega CD games (especially ones that require a RAM cart like Shining Force CD), the Mega Everdrive wins in my book.

I'm not familiar with the UMDK (just learned about it because of this thread, actually), but from the sounds of it, it seems very comparable to the standard Everdrive

tryphon · Post by **tryphon** » Thu Oct 09, 2014 1:43 pm

I was interested in a Mega-CD, but its price is really prohibitive (to be true, I was more interested in 32X, but it's even more prohibitive).

I just don't understand why Sega put another processor in the MegaCD (the MD 68000 was doing a fine job), and another better VDP...

MintyTheCat · Post by **MintyTheCat** » Wed Oct 22, 2014 3:59 pm

elusive wrote:I had both versions of the Everdrive, and if you're into playing Sega CD games (especially ones that require a RAM cart like Shining Force CD), the Mega Everdrive wins in my book.

I'm not familiar with the UMDK (just learned about it because of this thread, actually), but from the sounds of it, it seems very comparable to the standard Everdrive

UMDK is nothing like the Everdrive or Mega Everdrive.

Mega Everdrive allows a person to upload a ROM image to its internal memory and then execute that ROM and it does this over USB.

UMDK is in fact a complete development tool that allows you to trace every single action on the MD's Address Bus. You can perform the usual debug actions such as single-step, interrogate 68K Registers, peek and poke WRAM, etc.
From this and by using the Trace functionality you can see EXACTLY which part of the code is executed and you can stop the execution of your ROM or Game ROM to the granularity of a Video Sync Interrupt.

You can search the Trace-Log having executed your ROM and search for VDP and 68K actions - which is very very very useful when you are debugging VDP code - and that's pretty much a fair chunk of all the work a Game on the MD performs.

Much more in the way of Tools will be developed to support UMDK but the Trace facility alone and the Debug will literally save Developers Hours of work. I speak from experience here.

Here is an example from a Trace-Log, I will put some code up later to show you EXACTLY what is being carried out on the real MD Hardware:

Code: Select all

C RD 000000 00FF 00FF
C RD 000002 FE00 FE00
C RD 000004 0000 0000
C RD 000006 0200 0200
C RD 000200 4AB9 4AB9
C RD 000202 00A1 00A1
C RD 000204 0008 0008
C RD 000206 6606 6606
...
D RD 0001BA 2020 2020
D RD 0001BC 554D 554D
D RD 0001BE 444B 444B
D RD 0001C0 2044 2044
...

1st Column: type of action: C: CPU 68K, D: DMA
2nd Column: read or write action
3rd Column: Program Counter when action took place
4th Column: value placed on 68K Address-Bus expected
5th Column: value placed on 68K Address-Bus actual

That is INCREDIBLY useful information that can be obtained from ROMs executing directly on the real MD Hardware.

UMDK *CANNOT* be compared with the Everdrive - the Everdrives are merely Flashcarts with a Game Genie patcher added.

Of course, UMDK also has an SD-Card slot if you wish to use it 'like any other Flashcart'.

For the price I do not think that there is much of a comparison. execution speed is a BIG issue to me and I do not want to be waiting for the Mega Everdrive to flash its ROM image. UMDK is lighting fast on the other hand.

The main criteria for me is whether or not you are a MD Developer or a MD Gamer. I can see Gamers opting for the Everdrive and Developers opting for the UMDK due to what can be achieved with UMDK.

Thank you.

MintyTheCat · Post by **MintyTheCat** » Wed Oct 22, 2014 4:02 pm

tryphon wrote:I understand this is worth considering (I've already read this thread more than once) but :

1) I'm used to emulators. I know UMDK offers uncomparable possibilities for debugging, but I'm from old school, I don't even use a debugger when I code in C or python

2) I don't know how much an UMDK would be (I saw 80 € in the thread but it wasn't confirmed)

3) I don't know how long it would take to get one (I didn't totally understand the aim of the thread).

I think UMDK is a little overpowered for my use, so unless its price speaks in its favour, I don't see the point to have one. But I may be wrong and am ready to change my mind

It depends on how accurate you want your code to be and how much you want when being able to debug your code.

It also boils down to if you want something that accurately runs on the real Hardware or are happy to have it run only on an Emulator.

The "Old-School" does not mean to develop without Debuggers. If you go back in time you will indeed find that SBC development boards included a full on debug system. Any one who thinks that they can get away with the "Printf Method" (which is not debugging) is a complete idiot in this day and age given how much we have in terms of debuggers these days. You fundamentally change the execution profile of your ROM/Binary/etc through the use of Printf and not mention how incredibly expensive Printf actually is - have you ever seen the size of Printf as part of CLib?

This is not the way to debug small ROM/Embedded systems and least of all anything that is meant to be Real-Time.

The choice is entirely yours.

The aim of the Thread that you saw is to have a batch of UMDK Kits manufactured for the MD Dev Community.

No, it is not listed at €80.

I hope that helps to clear up your questions.