TI threw a monkey-wrench into the works with their "2716". The predecessor -- 2708 -- required multiple supplies. Intel (and the rest of the Japanese suppliers) introduced
*the* 2716 as a "5V only" part (still needed Vpp for programming but could *run* the chip off 5V alone -- no need for multiple supplies).Folks quickly realized that they did NOT want TI's parts (purchasing agents who thought 2716 == 2716 soon learned that this was not the case... recall that 2716's were approaching the $50/ea price at one point so a naive purchasing agent could easily screw himself by "finding" a bunch of "2716's" at a "real good price" :> ). So, TI had to come up with a "TI" 2716 -- though they already had used the 2716 P/N. Hence the 2516 was born. (i.e., a TI 2516 is the same as an intel 2716)
Not content with shooting themselves in the foot with *their*
2716, TI then went on -- in their infinite stupidity -- to shoot themselves in the *other* foot by coming out with a 2532 THAT WAS NOT EQUIVALENT to the rest of the world's 2732!Point being: make sure you know *which* chip you are trying to emulate.
As an aside, it is amusing to look back at the die for these devices. Intel had these *tiny* die while folks like Hitachi had these big monstrosities (though functionally equivalent). Yet, they (Hitachi) managed to make a good show of it (financially). Probably had Milo Minderbinder on their sales staff :-/
--don