68300

Hello All,
      I am using an AT49F8192-90RC(512K * 16) FLASH with the 68332. 
The problem i am facing is that since this part works on 5 V logic, it is 
getting more and more difficult to procure.

       The 3.3 V equivalents are easier to get. Is it possible to connect 
a 3.3 V FLASH device to the 68332 and still be working reliably.

       Is anybody aware if Motorola is coming up with a 3.3 V version of 
the 68332.


Thanks & Regards,
Philip Jones,
Engineer,
R&D Department,
ID Technologies. (A division of mark elektriks)
============================================================
B1/1, Sai Sahawas Apt.,  | Phone: +91-20-4003315, 4007158
Oppo. Corporation Bank,  | TeleFax: +91-20-5410479
Maharshi Karvenagar,     | Email: development@...
Hingne (Bk),             | www.markelektriks.com
Pune - 411052. India.    |
============================================================

Phil,

As a matter of interest, almost all of the MC68332 devices will work at 3.3 volts.  However, Motorola does not offer a 3.3 volt selection anymore.  The reason was that it was a very low volume part.

So, you can (at your own risk) just try running the '332 at 3.3 volts.  The first issues you will hit are the oscillator start up time and you may have to jockey around with the XFC filter components.  Probably, all you will need to do is lower the value of the series resistor for the crystal.

Having said that, you are correct in that the 5 volt 68332 has incompatible voltage levels with a 3.3 volt flash.  You are going to have to use some type of voltage interface between the two devices.

Regards,

Charlie

-----Original Message-----
From: development [mailto:development@...]
Sent: Friday, August 06, 2004 5:21 AM
To: 68300@yahoogroups.com
Subject: [68300] Connecting a 3.3 V logic to a 5V logic processor.
Importance: High


Hello All,
      I am using an AT49F8192-90RC(512K * 16) FLASH with the 68332. 
The problem i am facing is that since this part works on 5 V logic, it is 
getting more and more difficult to procure.

       The 3.3 V equivalents are easier to get. Is it possible to connect 
a 3.3 V FLASH device to the 68332 and still be working reliably.

       Is anybody aware if Motorola is coming up with a 3.3 V version of 
the 68332.


Thanks & Regards,
Philip Jones,
Engineer,
R&D Department,
ID Technologies. (A division of mark elektriks)
============================================================
B1/1, Sai Sahawas Apt.,  | Phone: +91-20-4003315, 4007158
Oppo. Corporation Bank,  | TeleFax: +91-20-5410479
Maharshi Karvenagar,     | Email: development@...
Hingne (Bk),             | www.markelektriks.com
Pune - 411052. India.    |
============================================================





 
Yahoo! Groups Links

Hello all,
This isn't actually a question about the 683xx, but for the HCS12DP256.
Some I/O pins have the capability of full (10ma) drive and 1/3 drive 
settings.
What is the reliability of the processor if I drive a full drive pin to 
VCC and connect it via a (approx) 50 ohm resistor to an other pin 
driven low with 1/3 drive? This contention would last for ~ 200 
microseconds out of a period of 40 milliseconds. 0.5% duty cycle 
effectively.
Basically like an active pull down.

or please point me in the correct direction.

Tim Flynn

Tim,

I would not do this.  It creates a lot of noise on the board.  You are 
trying to force 100ma thru two pins on the processor.  The pins rated at 
10ma will source a lot more than 10ma. the same for the 1/3 drive 
pins.  You will not know what voltage is generated on either end of the 
resistor when the contention happens.

Maybe there is some other solution to the design you are trying to accomplish.



At 08:06 AM 4/5/2005, you wrote:

>Hello all,
>This isn't actually a question about the 683xx, but for the HCS12DP256.
>Some I/O pins have the capability of full (10ma) drive and 1/3 drive
>settings.
>What is the reliability of the processor if I drive a full drive pin to
>VCC and connect it via a (approx) 50 ohm resistor to an other pin
>driven low with 1/3 drive? This contention would last for ~ 200
>microseconds out of a period of 40 milliseconds. 0.5% duty cycle
>effectively.
>Basically like an active pull down.
>
>or please point me in the correct direction.
>
>Tim Flynn
>
>
>
>
>Yahoo! Groups Links
>
>
>
>
Sincerely,

Robert E. Yablonski


Hunt Dabney & Associates
Electronic System Development and Design
1366 Logan Ave, Suite B
Costa Mesa, CA 92626
--------------------------------------------------------------------
http://www.huntdabney.com
fax: (714) 540-8131
714 540-2372 X104



[Non-text portions of this message have been removed]

After further research, what I am doing appears to be fine.
A 1/3 drive can sink about 8-10 ma. A Full drive output can source up 
to about 60ma.
Connecting these together, and drive the Full high and the 1/3 low is 
limited by the 1/3 drive output to about 10ma. This is within pin 
limits.

On Apr 5, 2005, at 1:34 PM, Robert Yablonski wrote:

>
> Tim,
>
> I would not do this.  It creates a lot of noise on the board.  You are
> trying to force 100ma thru two pins on the processor.  The pins rated 
> at
> 10ma will source a lot more than 10ma. the same for the 1/3 drive
> pins.  You will not know what voltage is generated on either end of the
> resistor when the contention happens.
>
> Maybe there is some other solution to the design you are trying to 
> accomplish.
>
>
>
> At 08:06 AM 4/5/2005, you wrote:
>
>> Hello all,
>> This isn't actually a question about the 683xx, but for the 
>> HCS12DP256.
>> Some I/O pins have the capability of full (10ma) drive and 1/3 drive
>> settings.
>> What is the reliability of the processor if I drive a full drive pin 
>> to
>> VCC and connect it via a (approx) 50 ohm resistor to an other pin
>> driven low with 1/3 drive? This contention would last for ~ 200
>> microseconds out of a period of 40 milliseconds. 0.5% duty cycle
>> effectively.
>> Basically like an active pull down.
>>
>> or please point me in the correct direction.
>>
>> Tim Flynn
>>
>>
>>
>>
>> Yahoo! Groups Links
>>
>>
>>
>>
> Sincerely,
>
> Robert E. Yablonski
>
>
> Hunt Dabney & Associates
> Electronic System Development and Design
> 1366 Logan Ave, Suite B
> Costa Mesa, CA 92626
> --------------------------------------------------------------------
> http://www.huntdabney.com
> fax: (714) 540-8131
> 714 540-2372 X104
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
Tim Flynn
Director of R&D
RMS Welding Systems
Ph.(780)955-3907
http://www.rmsweldingsystems.com