20 Jan
2003
20 Jan
'03
9:48 a.m.
From: "Philip Pemberton"
<philpem(a)dsl.pipex.com>
Stan Barr wrote:
This is the EA pin. It controls where the program memory is.
The 8031 ( 8032 ) is the version that is sold to be used this
way. As far as I know, the 8031's are just units that the
mask part failed or overruns of mask 8051 parts. Early
on, 8031's, with EPROMs were more common in keyboards and newer
keyboards use just 8051's.
Dwight
I use
While looking for some op-amp chips earlier I
came across a
couple of 8751s (labelled Intel '80). A quick google search
failed to turn up a data sheet, anyone any ideas where I can
look?
IIRC, the 8751 is an EPROM (windowed package) version of the 8051 MCU. The
thing about the 8051 (and the 8052) is that it can also be used as a CPU -
add a 74LS573 (or 74LS373) latch and a bit of decoding and you can disable
the internal program memory and use external memory instead. 8051-derivatives a fair bit - Atmel's AT89S8252 is
a particularly nice
chip - basically an 8052 with 8k of internal FLASH memory and an SPI
programming interface.
Later.
--
Phil.
philpem(a)dsl.pipex.com
http://www.philpem.dsl.pipex.com/