6802 clock

[Lee K. Gleason]

I'm building a simple 6802 single board system. I want to drive the CPU
with an external oscillator, rather than using a crystal (got lots of 4 pin
oscillators, not so many crystals). When using a crystal, the frequency of
the crystal gets divided down by 4 by an internal part of the processor (so
you use a 4 MHz crystal for a 1MHz clock).

When using an external oscillator, like I want to do, does the same divide
by 4 occur? That is, should I use a 4 MHz external oscillator, or a 1 MHz
oscillator for a 1 MHz system clock?

Lee K. Gleason N5ZMR
Control-G Consultants
lgleason@houston.rr.com

 

[John Fields]

On Thu, 21 Jul 2005 23:07:49 GMT, "Lee K. Gleason"
<lgleason@houston.rr.com> wrote:

I'm building a simple 6802 single board system. I want to drive the CPU
with an external oscillator, rather than using a crystal (got lots of 4 pin
oscillators, not so many crystals). When using a crystal, the frequency of
the crystal gets divided down by 4 by an internal part of the processor (so
you use a 4 MHz crystal for a 1MHz clock).

When using an external oscillator, like I want to do, does the same divide
by 4 occur? That is, should I use a 4 MHz external oscillator, or a 1 MHz
oscillator for a 1 MHz system clock?

---
You'll need a 4MHz oscillator.

--
John Fields
Professional Circuit Designer

 

[Bozzion]

"Lee K. Gleason" <lgleason@houston.rr.com> wrote in message
news:9VVDe.11159$gL1.10218@tornado.texas.rr.com...

I'm building a simple 6802 single board system. I want to drive the CPU
with an external oscillator, rather than using a crystal (got lots of 4
pin
oscillators, not so many crystals). When using a crystal, the frequency of
the crystal gets divided down by 4 by an internal part of the processor
(so
you use a 4 MHz crystal for a 1MHz clock).

When using an external oscillator, like I want to do, does the same
divide
by 4 occur? That is, should I use a 4 MHz external oscillator, or a 1 MHz
oscillator for a 1 MHz system clock?

Lee K. Gleason N5ZMR
Control-G Consultants
lgleason@houston.rr.com

why not? isn't the devider on chip?

 

[Frank]

By the way who makes the 6802, is Motorola still around?

Lee K. Gleason <lgleason@houston.rr.com> wrote in message
news:9VVDe.11159$gL1.10218@tornado.texas.rr.com...
I'm building a simple 6802 single board system. I want to drive the CPU
with an external oscillator, rather than using a crystal (got lots of 4 pin
oscillators, not so many crystals). When using a crystal, the frequency of
the crystal gets divided down by 4 by an internal part of the processor (so
you use a 4 MHz crystal for a 1MHz clock).

When using an external oscillator, like I want to do, does the same divide
by 4 occur? That is, should I use a 4 MHz external oscillator, or a 1 MHz
oscillator for a 1 MHz system clock?

Lee K. Gleason N5ZMR
Control-G Consultants
lgleason@houston.rr.com

 

[John Fields]

On Sat, 23 Jul 2005 01:52:00 +1200, "Frank" <some1not@microsoft.com>
wrote:

By the way who makes the 6802, is Motorola still around?

---
Motorola spun off their ľC product line to Freescale Semiconductor,
but I don't think you're going to find much 6802 around, since it's
been obsolete for a while.

Freescale suggests Rochester Electronics as a possible source, and
Google will give you lots of hits. If what you're doing is new, why
do you want to use a 6802 anyway?

If you choose to reply, it's considered, in this group, to be
courteous if you bottom post.

--
John Fields
Professional Circuit Designer

 

[Frank]

No I was just asking?
Motorola came up with a good range of micro, I went to a few of there
seminars, back in the 70's


John Fields <jfields@austininstruments.com> wrote in message
news:4852e1h6j3u97fvp443n5jg4vt92p6gh04@4ax.com...
On Sat, 23 Jul 2005 01:52:00 +1200, "Frank" <some1not@microsoft.com>
wrote:

By the way who makes the 6802, is Motorola still around?

---
Motorola spun off their ľC product line to Freescale Semiconductor,
but I don't think you're going to find much 6802 around, since it's
been obsolete for a while.

Freescale suggests Rochester Electronics as a possible source, and
Google will give you lots of hits. If what you're doing is new, why
do you want to use a 6802 anyway?

If you choose to reply, it's considered, in this group, to be
courteous if you bottom post.

--
John Fields
Professional Circuit Designer

 

[Karl Uppiano]

"Frank" <some1not@microsoft.com> wrote in message
news:42e176a5@clear.net.nz...

No I was just asking?
Motorola came up with a good range of micro, I went to a few of there
seminars, back in the 70's


John Fields <jfields@austininstruments.com> wrote in message
news:4852e1h6j3u97fvp443n5jg4vt92p6gh04@4ax.com...
On Sat, 23 Jul 2005 01:52:00 +1200, "Frank" <some1not@microsoft.com
wrote:

By the way who makes the 6802, is Motorola still around?

---
Motorola spun off their ľC product line to Freescale Semiconductor,
but I don't think you're going to find much 6802 around, since it's
been obsolete for a while.

Freescale suggests Rochester Electronics as a possible source, and
Google will give you lots of hits. If what you're doing is new, why
do you want to use a 6802 anyway?

Sometimes a good 8-bit 1 MHz processor is all you need.

 

[Pooh Bear]

Frank wrote:

No I was just asking?
Motorola came up with a good range of micro, I went to a few of there
seminars, back in the 70's

You just 'top posted' btw !

Graham