External Memory Bus for 8051

[Andy Roark]

Hello everyone,

Can anyone direct me toward a schematic/instructions for setting up an
external memory bus from Port 0/2 of an 8051 mC. I am pretty sure I
am going to use a 373 latch, a 28C64A EPROM and a 22V10. Again, i'm
pretty sure i'm almost there but this is my first one and would like
to compare what I have drawn out with something else before I break
out the wire wrap tool.

Thanks for any help.

 

[Ken Smith]

In article <47rs019oph1e8he9j11hj1qllrl8bd1ap9@4ax.com>,
Andy Roark <andyroark@nospam.comcast.net> wrote:

Hello everyone,

Can anyone direct me toward a schematic/instructions for setting up an
external memory bus from Port 0/2 of an 8051 mC. I am pretty sure I
am going to use a 373 latch, a 28C64A EPROM and a 22V10. Again, i'm
pretty sure i'm almost there but this is my first one and would like
to compare what I have drawn out with something else before I break
out the wire wrap tool.

What's the 22V10 for?

Why not a HCT273 instead of the 373?

Why not a 27C512 socket with the needed option jumpers for 28C64, 27C128
etc?


Why not also make it take 2 chips, static RAM and a PROM? If you do, I
can think of a used for the 22V10. You can make it so that the RAM can be
switched in and out of the code space.

--
--
kensmith@rahul.net forging knowledge

 

[Anthony Fremont]

"Andy Roark" <andyroark@nospam.comcast.net> wrote in message
news:47rs019oph1e8he9j11hj1qllrl8bd1ap9@4ax.com...

Hello everyone,

Can anyone direct me toward a schematic/instructions for setting up an
external memory bus from Port 0/2 of an 8051 mC. I am pretty sure I
am going to use a 373 latch, a 28C64A EPROM and a 22V10. Again, i'm
pretty sure i'm almost there but this is my first one and would like
to compare what I have drawn out with something else before I break
out the wire wrap tool.

Thanks for any help.

Check out the 74xx573 instead of the 373, you may like the pinout
better.

Look here for 805x stuff:
www.8052.com

 

[martin griffith]

On Sun, 13 Feb 2005 09:48:21 -0500, in sci.electronics.design Andy
Roark <andyroark@nospam.comcast.net> wrote:

Thanks for the link.
snip.

Yes, we are using

older parts but such is the norm in education I think. Plus they are
cheap to replace when I blow them up.
ARGHH...

You are still using EPROMs? what a waste of time, 20 min erase cycle
IIRC. How long is a lesson these days, maybe 3 or 4 erase cycles.

Sorry but I think it is utterly STUPID to use EPROMs when you can
burn a flash 8051 8K in 30 seconds or so. Tell the teacher I said so!
(sorry for the rant)

Primarily I was looking for information on the basic layout (I found a
pretty decent schematic) and also information on exactly how to
interface the LCD/Keypad/etc back to the bus.

The www.8052.com website was very helpful. Thank you for providing
it.

Andy

Check out the 74xx573 instead of the 373, you may like the pinout
better.

Look here for 805x stuff:
www.8052.com

martin


"Facts are stupid things.." -- Reagan, '88

 

[Ken Smith]

In article <oetu01pmu731s5o1pla1ieeftq8pmqcaj4@4ax.com>,
martin griffith <martingriffithX@Xyahoo.co.uk> wrote:
[...]

Sorry but I think it is utterly STUPID to use EPROMs when you can
burn a flash 8051 8K in 30 seconds or so. Tell the teacher I said so!
(sorry for the rant)

Better yet, hook up a static RAM so you can run out of it.

You could then download the program and have it crash in under 10 seconds.

--
--
kensmith@rahul.net forging knowledge