Saturn region-free BIOS: clarification needed

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I have some M29F800AB, so I will try it here.

 

Not going to be able to try this for a week or so.

However, if it is the boot block... just program the bios twice to the chip (concatenate same file twice, so chip is full) and the extra address line on pin 2, connect it to VCC instead...

This way, you are using the middle of the chip, rather than top or bottom. Not that I think thats the problem, but it should rule it out.

 

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Sorry, I confused the chip you have, with the bottom boot ones I have.

Will report when I have results

 

x

 

It's on my todo list, but no not yet.

There is no reason I can think of for it not to work, as it's only to do with protection and erasing of sectors. Reading is the same on top and bottom.


I will install a socket, so I can test original bios in the socket to confirm the install then put in a bottom boot chip

 

To Druid II: I assume that the access time of your eeprom is too low. You said that you are using a "AM29F400AB-70SC", this means 70ns access time. You should use 90ns eeproms. Probably someone else can clearify the access time issue (if there is one).

 

70ns is faster than 90ns.

Lower is fine, too high is bad. It's fastest response time.

Also, relating to druids post - I tested top and bottom boot chips and they work as expected.

 

Hello,
This is compatible with AM29F400BT?
Same schema?

Thanks

 

Yes it's compatible. Don't need the wire to last address line though.

 

Ok because I install like that :

Pin 2 lift > Pin 13 (GND)
Pin 43 and 44 lift > Pin 23 (5V)

But doesn't work black screen ^^

I flashed with this bios "GameNavi HiSaturn 1.03 (RF).bin"... no problem no?

 

Did you byte swap the bios before programming it?

 

Hummm.. no just program like dreamcast bios..so I think it's the problem? ^^

I have a GQ-4x4 can you explain how please

 

Load rom, press byte swap, program chip.

Assuming it's the same as the gq-4x I used to have.

 

When I load rom I have :

Format : Binary (.bin)..

Mode lecture : Normal .. Even Byte.. Odd Byte...

Remplissage : Normal ... Fill 'FF' ... Fill '00'

Offset

So what I do change ?

 

Ok I found,there is a button A-B "Byte Swap",and when I click the buffer change.

Can you explain why need byte swap and what is it?

Thank you again for your help

 

To account for the endianness of target system.

 

Ok

So not need to put Pin 2 To GND in fact.

Why in a other tutorial link Pin 2 to Pin 13?

Or maybe not necessary with this chip?

Thanks