Sega TeraDrive Max Memory

Hello guys!

Im trying to push some limits of my Teradrive. I know the max memory documented is 2.5 megs, is there anyone around here who tried to use different SIMMs, bigger than 1 meg?
I read that the 286 processor can handle around 16 megs of memory.

Thanks! :smile-new:

 

If cheap components were used for the TeraDrive it may very well only support 2.5mb of RAM. The 286 CPU can address more than that IIRC (probably 16mb or more) but you're limited to what the chipset can address and what SIMM sticks you can find that are compatible.

Wish I had held onto those low density SIMM sticks I had. 4x32mb matched sticks seem to be very hard to find these days.

 

I found a set on Ebay, I think I will buy it to test, these are 10 dollars anyway...

 

That'd have no effect on the MD side of it, would it?

 

Nope. Despite the Teradrive being able to do DEV work on the Mega side, they are still separate systems hardware wise. No memory or CPU sharing.

 

Althought the 286 can address 16mb of memory the Sega Terradrive does not have the high address lines connected from the 30pin SIMMs, so although you could technically use 4mb SIMMs you would still only see 2.5MB (512K on board memory and the 2 x 1mb it would see from the SIMMs).

One way you could get extra memory is to use a ISA EMS RAM card but you really would need a good reason to do so...

 

Thanks for explaining that to me, that makes complete sense. :friendly_wink:

 

Out of curiosity, which model were you running there? Model 3?