8085 vs 8085A
ajp166 at bellatlantic.net
Tue Aug 7 06:51:56 CDT 2007
>Subject: Re: 8085 vs 8085A
> From: "Steven Canning" <cannings at earthlink.net>
> Date: Tue, 07 Aug 2007 01:11:07 -0700
> To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org>
>> 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
>> 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?
>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
It was. Supposededly the 8085 was used to proto the intel CMOS process
for the 80C48 and 80C188 and later parts.
>two second source manufacturers - OKI and Tundra Semiconductor. Tundra
>Semiconductor manufactured the fastest 8085 microprocessor running at 8 MHz.
I have a few 8mhz intel 8085AH-2s (16mhz clock crystal) HMOSII, those are
scarce but do exist. Intel did make the 8085AH (HMOSII) at 6mhz as well.
>Second source manufacturers: AMD, Mitsubishi, NEC, OKI, Siemens, Toshiba.
I have parts from all of them. I find the 8085 and Z80 to be good workhorse
8 bitters. Both enjoyed long sales lives.
>Best regards, Steven C.
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