6502A/B/C Release dates

[VinCBR900]

Hi,
just pondering on the evolution of NMOS 6502 increased clock speed variant before 65C02.

Anyone got any magazine links to appropriate articles?

Thx

[GARTHWILSON]

I don't have such links, but you could look at old data sheets.  I imagine the "binning" existed right from the beginning.  The "bins" are not actual bulk containers, but classifications for sale.  For an EPROM, the "bins" might be for example 55ns, 70ns, 100ns, and 120ns.  The parts are tested, and each one is put into the fastest bin that it passes the test for.  So imagine a part marked 100ns.  It might have been 71ns, which is faster than marked, but not fast enough to make it into the 70ns bin.  Or it might have been 99ns. You don't know.  They can charge a little more for the faster ones, without throwing out the slower ones.

In the late 1970's Bill Mensch had NMOS 6502's running at 10MHz.  That doesn't mean they would pass all the timing margin guarantees at that speed, or that they were guaranteed to run at 10MHz under the whole temperature range.  He tells that early production testing was done on a crude, home-made manual tester, and they required each part to work at twice the speed they'd mark it for.  If I understood it correctly, the tester was hand-made to approximate the timings of the accompanying parts that a 6502 of so many MHz would have to operate with, which implied that the 6502 met the remainder of the timing margins, and then if it worked at 4MHz, they'd mark it for 2MHz, and if it failed to work at 4MHz, even by the slimmest of margins, it was marked for 1MHz.  IOW, a 1MHz might have actually worked at 3.9MHz, at room temperature.

[BigEd]

There might be historical price lists. My feeling is that 2MHz 6502 took quite a while to turn up.

[GARTHWILSON]

I see the May '76 data sheet shows a 2MHz version:
http://6502.org/documents/datasheets/mo ... y_1976.pdf

and the 1980 data sheet shows a 3MHz version:
http://6502.org/documents/datasheets/mo ... r_1980.pdf

and the 1985 data sheet has a 4MHz version:
http://6502.org/documents/datasheets/mo ... v_1985.pdf

[VinCBR900]

Perfect, thanks gents! Wikipedia doesn’t really discuss.