Hi Folks,
I need a push button that will drive a single pulse of XTAL-1 each time I
press it and in turn the chip will respond with 8 bits which I
would like to read manually by LEDs. Would I need something like a LS245
data latch to catch the data for the LED's to be stable??
A battery would provide the power for the chip & XTAL.Please keep it as
simple as possible as I'm not schooled in electronics.

thanks in advance.
--
Ian Turnbull
Tel: 07961 931941
Fax: 0870 137 1834

Well Ian,

Your explanation needs a bit more. You press a button and the 'chip'
responds with 8 bits? XTAL-1?

Is this chip counting your button presses? Are the 8 bits randomly
generated?



Jay

an 8 bit port on the AT89C4051 microcontroller

"rw" wrote in message
...


Ian T wrote:
Hi Folks,
I need a push button that will drive a single pulse of XTAL-1 each time
I
press it and in turn the chip
question: what chip? will respond with 8 bits

question: what 8 bits? what makes the 8 bits?
which I
would like to read manually by LEDs. Would I need something like a LS245
data latch to catch the data for the LED's to be stable??
A battery would provide the power for the chip & XTAL.Please keep it as
simple as possible as I'm not schooled in electronics.

thanks in advance.
--
Ian Turnbull
Tel: 07961 931941
Fax: 0870 137 1834

Well Jay,
That's why I posted here to get knowlegable people's help, like yours. 27
years experience I can't pick up from a couple of books!!
Thanks for the info but I'd rather have a simple circuit than to have to
read books on both electronics and micrcontrollers.
But, well thanks for the info but a circuit would have been better? That's
what I asked for!

"happyhobit" wrote in message
...
Well Ian,

The AT89C4051 is a 3Volt, 80C31 Microcontroller with 4K bytes Flash,
20-Pin
Package. XTAL-1 and XTAL-2 is where the 24 MHz crystal, that clocks the
microcontrolled, would be connected. You could also use an external clock
signal and feed it into XTAL-1 to Ground.

Check out the Atmel website. http://www.atmel.com/

And for the AT89C4051;


http://www.atmel.com/dyn/products/pr...04&family_name
=8051+Architecture&part_id=1939

The 'Location Counter' you mention is probably the Program Counter. This
keeps track of the instructions the microcontroller is executing.

Pins 4 and 5 are XTAL-1 and XTAL-2.



If your not familiar with microcomputers / microcontrollers you probably
need to pick up a couple of books and start reading.



I did, 27 years ago. : )



Jay

The chip you mention can work from a pulse on the xtal pin. The circuit you
need is called a monostable timer, NE555 timer IC can be set in this mode,
loads of circuits on the net! the latch you mention is not required as the
port will latch its self. The leds can be connected to ground though a
resistor on each LED.

It is not very likely that the program the CPU is running will output to the
port very often though.

There are a lot of books on the subject of microcontrollers but if you want
a simple start into the subject you could buy a starter kit. These have lots
of doc's with them and although it's not easy, you can get a great deal from
these devices. Consider on a FLASH based device that can be reprogrammed and
with in-system program parts like ATMEL avr it's very simple and neat.

Have fun

Geoff Hackett
Senior Electronics Engineer

"Ian T" wrote in message
...
an 8 bit port on the AT89C4051 microcontroller

"rw" wrote in message
...


Ian T wrote:
Hi Folks,
I need a push button that will drive a single pulse of XTAL-1 each
time
I
press it and in turn the chip
question: what chip? will respond with 8 bits

question: what 8 bits? what makes the 8 bits?
which I
would like to read manually by LEDs. Would I need something like a
LS245
data latch to catch the data for the LED's to be stable??
A battery would provide the power for the chip & XTAL.Please keep it
as
simple as possible as I'm not schooled in electronics.

thanks in advance.
--
Ian Turnbull
Tel: 07961 931941
Fax: 0870 137 1834

Thanks Geoff
much appreciate your input. Being a total novice could you recommend a
starter kit or perhaps point me in the correct direction.
Cheers,

"Geoff Hackett" wrote in message
...
The chip you mention can work from a pulse on the xtal pin. The circuit
you
need is called a monostable timer, NE555 timer IC can be set in this mode,
loads of circuits on the net! the latch you mention is not required as the
port will latch its self. The leds can be connected to ground though a
resistor on each LED.

It is not very likely that the program the CPU is running will output to
the
port very often though.

There are a lot of books on the subject of microcontrollers but if you
want
a simple start into the subject you could buy a starter kit. These have
lots
of doc's with them and although it's not easy, you can get a great deal
from
these devices. Consider on a FLASH based device that can be reprogrammed
and
with in-system program parts like ATMEL avr it's very simple and neat.

Have fun

Geoff Hackett
Senior Electronics Engineer

"Ian T" wrote in message
...
an 8 bit port on the AT89C4051 microcontroller

"rw" wrote in message
...


Ian T wrote:
Hi Folks,
I need a push button that will drive a single pulse of XTAL-1 each
time
I
press it and in turn the chip
question: what chip? will respond with 8 bits

question: what 8 bits? what makes the 8 bits?
which I
would like to read manually by LEDs. Would I need something like a
LS245
data latch to catch the data for the LED's to be stable??
A battery would provide the power for the chip & XTAL.Please keep it
as
simple as possible as I'm not schooled in electronics.

thanks in advance.
--
Ian Turnbull
Tel: 07961 931941
Fax: 0870 137 1834