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No swap needed. There is little endian and big endian type of CPUs.

https://en.wikipedia.org/wiki/Endianness
And because Sega ST-V is SuperH architecture, which is Big Endian, it doesn't need its byte swapped?
Endianness is the order of the bytes that compose a digital word in computer memory. It also describes the order of byte transmission over a digital link. Words may be represented in big-endian or little-endian format. When storing a word in big-endian format the most significant byte, which is the byte containing the most significant bit, is stored first and the following bytes are stored in decreasing significance order with the least significant byte, which is the byte containing the least significant bit, thus being stored at last place.
But how can you tell if your to be flashed .bin is ready for big or little endian?
 
And because Sega ST-V is SuperH architecture, which is Big Endian, it doesn't need its byte swapped?But how can you tell if your to be flashed .bin is ready for big or little endian?
The M27C400 is a 4 Mbit (512Kb x8 or 256Kb x16). It can be operated in 8 bit mode or 16 bit mode. Most EPROMs which have a "dual" organization will program and read out in byte mode so everything is OK.
 
Ok, I get the .bin is in the correct format :) I'm not arguing that, I'm just trying to figure out how I can determine if it's ok myself.

Byte mode is always big endian? Forgive me if I'm being stupid.

/edit

Nevermind :D

I read SuperH is big endian when the wikipedia page actually says it's bi-endian

Bi-endianness
Some architectures (including ARM versions 3 and above, PowerPC, Alpha, SPARC V9, MIPS, PA-RISC, SuperH SH-4 and IA-64) feature a setting which allows for switchable endianness in data fetches and stores, instruction fetches, or both. This feature can improve performance or simplify the logic of networking devices and software. The word bi-endian, when said of hardware, denotes the capability of the machine to compute or pass data in either endian format.
Anyway I'll just keep my mouth shut and maybe come back in case I might have some intelligent questions.. :D
 
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The SH2 itself is endian neutral (configurable at boot time) *but* as used on the SEGA Saturn and SEGA TitanVideo hardware it's used on big endian mode.

Having to byte swap or not depends more on the chip programmer than on the kind of chip you're programming. My cheap Chinese TOP2048 programmer will program the file as is. Some programmers may try to fix the endian.

So if you're using a little endian platform (x86-ish PC regardless of OS) open the file in a hex editor/viewer and see if it's readable in plaintext. If it is, it may need to be byte swapped.

If the file you're trying to use was taken from a zip file intended for use with MAME it's already correct and can be programmed as is (assuming your programmer won't byteswap the file).
 
The EPROM from HK came in today but still the same result. ;(

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I tried several games, all run with short flash and then black screen and the TV's scart source input OSD symbol comes on.

Accept for Pebble Beach Golflinks: The Great Shot which runs fine and for Astra Super Stars which boots, splash screens are fine but after the intro I get this:


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So this is definitely a hardware issue ;(
Any idea's?
 
I'll concentrate on that area then, thanks for the tip!
 
Astra Super Stars won't work because it is encrypted and hasn't been hacked yet. There are a few games like that.
 
The board will boot without the slave SH2. A lot of games use only the master SH2, even on Saturn games.
 
Astra Super Stars won't work because it is encrypted and hasn't been hacked yet. There are a few games like that.
So the artifacts are actually caused by the protection? The textfile of the roll up pack actually says protected behind the title. Didn't realize protection presents itself in this fashion :) thought it would not run period?

I found out that Karaoke Quiz Intro Don Don! and Golden Axe : The Duel work OK as well..
Is this because those titles rely on 1x (master) SH2?

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Which of the 2 is master? Or is this dynamic?

stv_pcb.png
 
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Look, the slave SH2 is supposed to run with it's own cache memory as program storage (so the bus is kept free for the main SH2 to do it's thing). That means address errors (address pins or control lines not connected) on the slave SH2 might not be caught by the self test. I'd suggest have them both re-soldered as there might be cracks on the solders.

And no, the master is always master, slave is always slave. Usually the master has the lowest "ICxx" number on the board mask.

The slave SH2 is often used to decrypt or unzip compressed stuff. Which would explain the horrible red screens on the game you posted (graphics failing to decompress perhaps?).
 
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