8051 question

[Fritz Oppliger]

On those 8051 models that have built in XRAM, does one get to use all the
ports that are otherwise used for AD0...AD15?
what I'm looking for is a 8051 with 64K Flash and about 16K RAM
and about 32 I/O pins.

 

[Denis Jeanroy]

No.
the internal XDATA area is accessed directly by the processor, without using
address or data ports like for external XDATA.
But an address is read out of the internal XDATA bank, ports will be used.
most 805x with internal XDATA have a setup option to use or not this
internal ram. So it is possible to use external ram only though AD ports.

if the application works with the internal XDATA range only, ports are
available for user I/O.

Denis

 

[Bruce]

On those 8051 models that have built in XRAM, does one get to use all the
ports that are otherwise used for AD0...AD15?
what I'm looking for is a 8051 with 64K Flash and about 16K RAM
and about 32 I/O pins.

Check with http://www.maxim-ic.com They have the Dallas DS series 8051
with 32, 64, or 128kB of NV CMOS SRAM.

You set the internal partition to divide program/data code space. Access to all
xdata space is handled internally giving you full access to all xdata without
wasting I/O-pins.

You set the partition to whatever size you need for program/data code space. Real
nice chips. I've used the DS5000 series in many applications.

Regards,

-Bruce
[email protected]
http://www.rentron.com

 

[Edwin Bland]

I believe what used to be Cygnal also has parts that fit what you're looking
for.