Help with MC68HC908AZ60 2J74Y chip please.

On 31 Dec 2008, 01:20, Rich Webb <bbew...@mapson.nozirev.ten> wrote:

On Tue, 30 Dec 2008 14:42:38 -0800 (PST), te...@hotmail.com wrote:
Found this....

http://www.etlweb.com/prod_prog_mc68hc908az60.html

Reading through the programmers user guide (PDF) it appears that the
protection code on the chip can be bypassed so that you can read
it...or that's how I read it...what do you think?

Well, there are 8 bytes that make up the security code. A brute force
approach has to contend with 2^64 possible combinations. The ROM monitor
that accepts (or not) the security bytes communicates at up to 28.8
KBaud. Each byte is echoed back, so the effective max rate is 14.4 KB.
With 2^64 combinations, and 8*(1+8+1) bits per combination (send 8 bytes
with start & stop bits, look for a break char, if not seen then reset
and try again), a worst-case condition would require 80*2^64/14400
seconds, or 102.5E15 seconds or about 1.2E12 days, not counting reset
time or testing for a break condition. If the expected value is half of
that, it's about 1.6E9 years.

At least, that's how I read the datasheet.

--
Rich Webb     Norfolk, VA

I haven't got that long...LOL

On the bright side it should start to warm up a little soon
(temprature) so the gauges will start to work ok again.