non-CP/M Z80 board
ajp166 at bellatlantic.net
Thu Jun 19 17:39:17 CDT 2008
>Subject: Re: non-CP/M Z80 board
> From: ard at p850ug1.demon.co.uk (Tony Duell)
> Date: Thu, 19 Jun 2008 04:42:01 +0100 (BST)
> To: cctalk at classiccmp.org
>> > I think the chips under discussion were the 8085 specialty chips,
>> > 8155, 8355, 8755, etc. Got tubes of those?
>> I've got a dozen or so 8755s, two or three 8155s, and no 8355s.
>> Not tube quantities, unfortunately.
>IIRC the 8355 was the mask-progeammed part, so it's not suprising you
>don't have any of those, If you did, they proably wouldn't contain the
>code you wanted :-).
Yes, but it' still useful as an IO device with 16 IO port lines that could
individually set for input or output.
>The 8755 was the EPROM part, and at least one
>version had a quartz windo for erasure (I don't know if there was an OTP
>type). The 8155 was RAM. All had I/O as well.
There was never an OTP, all were windowed Eprom devices.
the 8155 and the '56 were the same device save for CS polarity. they
are very useful with 256bytes ram, a programable timer/baud rate generator
and 22 IO pins that can be set as output, input or strobned outpus and inputs.
>There's also the 8156, which is the same as the 8155 (RAM + I/O) but with
>an active-high chip select. Not as common as the 8155.
Not as widely used but I have a bunch.
>Of course you can use normal RAM and EPROM with the 8085 is you add and
>address latch. An 74x373, or the 74x573 which as a saner pinout, is a
There was also the 8185 wich was a 1Kx8 ram with muxed address/data.
Those were uncommon as intel was the only supplier.
The 8085A (or A-5), 8755, 8155 in three chips gave 256bytes ram,
2Kbytes Eprom, 38 configurable port lines, A timer/baudrate generator,
4 interrupt lines and the handy SID and SOD IO pins. Very handy
for small applications. The base part ran at 3mhz (3.072mhz) and
the faster A-5 was a 5mhz (there were 6mhz HmosII and CMOS parts
Substitute a 8088 (or V20) and 8284A for the 8085 and you had a 16it
cpu with all the Eprom, ram and IO listed.
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