6 Aug
2007
6 Aug
'07
6:48 a.m.
Hi,
I was looking through my collection yesterday and was testing out an old
Intel SDK85 system. I noticed the main processor is stamped 8085, which
means this chip is either an 8085 or the "A" was not printed properly and
the chip is really an 8085A.
I have a few 8085 systems and a box of 8085 CPUs. I checked them all and
every one of them is an 8085A. I don't think I have ever seen an 8085,
they've all been 8085A types.
Other than the stamp on the chip, is there anyway I can tell the difference
between an 8085 and an 8085A? Furthermore, is the 8085 rare, and I should
put the chip away, or is it nothing special?
Why did Intel bring out the 8085A? Were there issues with the 8085?
Seeyuzz
River
6 Aug
6 Aug
3:25 p.m.
On 6 Aug 2007 at 20:48, river wrote:
Why did Intel bring out the 8085A? Were there issues
with the 8085?
I don't think that 8085's aren't particularly rare; basically the
original NMOS implementation. The 8085A fixed a few bugs--IIRC,
there were some issues in device selection timing (easily fixed with
a little "glue") and it seems to me that there was also a strange
race condition among the RST x.5 and TRAP interrupts. Maybe someone
remembers--the 8085a came along pretty quickly after the 8085.
Far better than either of the NMOS versions, however are the -AH
HCMOS models. Faster clocks and much lower power drain.
Cheers,
Chuck
7 Aug
7 Aug
4:11 a.m.
Hi,
I was looking through my collection yesterday and was testing out an old
Intel SDK85 system. I noticed the main processor is stamped 8085, which
means this chip is either an 8085 or the "A" was not printed properly and
the chip is really an 8085A.
I have a few 8085 systems and a box of 8085 CPUs. I checked them all and
every one of them is an 8085A. I don't think I have ever seen an 8085,
they've all been 8085A types.
Other than the stamp on the chip, is there anyway I can tell the
difference
between an 8085 and an 8085A? Furthermore, is the 8085
rare, and I should
put the chip away, or is it nothing special?
Why did Intel bring out the 8085A? Were there issues with the 8085?
Seeyuzz
River
There were multiple versions of 8085 microprocessors. The original version
of the 8085 microprocessor without suffix "A" was manufactured by Intel
only, and was very quickly replaced with 8085A containing bug fixes. A few
years after that, around 1980, Intel introduced 8085AH - HMOS version of
8085A. There was also 80C85A - CMOS version of the 8085A. It's not clear if
80C85 was ever manufactured by Intel or not, but it was produced by at least
two second source manufacturers - OKI and Tundra Semiconductor. Tundra
Semiconductor manufactured the fastest 8085 microprocessor running at 8 MHz.
Second source manufacturers: AMD, Mitsubishi, NEC, OKI, Siemens, Toshiba.
Best regards, Steven C.
6219
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