93S series eeproms

[VX L67 Getrag]

Hey All,

Just wondering if anyone has had much experience with the above mentioned eeproms?

The secure section of the eeproms has been said it can be read if putting pin 7 to ground but from what I read in the data sheet it actually says there’s a flag bit that allows read or write or erase of the protect register!
I actually just got a clean read off a 93S46W6 that even had leg 5 broken off it which is supposed to be ground voltage, so not sure how that works!

If anyone has any light to shed it would be great!

I know the 93S46 is only half the data size of the 93S56 but if I use a 56 in place of a 46 it should still work but will just have a different offset is this correct?

Thanks in advance VX L67 Getrag

[festy]

The 46 and 56 have different instruction sets, so you can't substitute them.

[VX L67 Getrag]

Oh Cool, thanks for the news festy, I guess I need to order some 93C46's then & just forget about secure section!

[antus]

The secure section of the eeproms has been said it can be read if putting pin 7 to ground but from what I read in the data sheet it actually says there’s a flag bit that allows read or write or erase of the protect register!

Just for reference, that is how most devices with security work. There is a flag which is usually a fuse internal to the chip and you can read/write untill you blow that fuse as part of the writing process. That way you can freely do what you want during development, then lock it up when you go to production. The fuses are internal to the chip, and cant normally be reset without pretty serious electronics lab gear. See here for an example: http://www.bunniestudios.com/blog/?page_id=40

[festy]

Oh Cool, thanks for the news festy, I guess I need to order some 93C46's then & just forget about secure section!

If you're in a bind and need to get hold of a 93C46 quickly, they're commonly used on PC peripherals like network cards, sound cards, scsi cards etc.

[VX L67 Getrag]

Thanks Antus good to know!

Thanks again festy, I have plenty of that stuff lying around the Mrs is bugging me to get rid of it so they may have found a new home!
EDIT; just went through box of stuff at home & looks most of it's too new as them seem to have AT24cXX chips, closest I've found is on an old dial up modem but it's 93LC46, so don't think that''l be any good, but have older gear at the workshop so will check when time permits at work!