Toshiba 4400 MIPs marking

[Neon_WA]

I am used to the ES marking on NEC MIPs not referring to Engineering Sample

but came across a Toshiba with ES marking and not really sure

early production & a low speed makes me wonder

here is CPUShack's for reference
http://www.cpushack.com/chippics/Toshiba/MIPS/ToshibaTC86R4400MC-75.jpg

Edit >> also this one of Gennas from the 4000 family
http://cdn.cpu-world.com/CPUs/R4000/L_Toshiba-TC85R4000SC-50.jpg

[jrmunro]

Out of my 6 Toshiba MIPS chips this is the only one I have with ES on it

[Neon_WA]

well dates on both correspond to when each family was released

4000 >> 1992
4400 >> 1993

on a side note this bit of info on CPUShack's site was interesting

The printed clock speed on early R4000 and R4400 processors is not the cpu clock speed, but the external clock speed, the internal speed is twice that value. Almost every website displays the wrong value for clock speed. So the NEC D30401RJ-50 VR4000SC-50 is actually a 100MHz chip. This was changed with the higher multiplier versions of the R4x00 (50MHz ext. / 200MHz int. / multiplier 4.0), this chips are marked with their internal clock speed.

so your TC85R4000SC-50 should be 100Mhz

[g0b]

So ES in this case would stand for External Speed ?

[Neon_WA]

[Neon_WA]

been looking at the various Toshiba MIPs and only the earliest in each family have the ES marking

Still not sold on being an ES, but I would consider them to be a QS or pre-production or not fully qualified at least

[bccwchan]