Re: Mondeo (III) Radio Code Question

In message <gldq15p8n9tgjp4hjaolqrpuo5flkpdneh@xxxxxxx>, Geo <hw9j-s5hw@xxxxxxxxxxxxxxx> writes
On Wed, 27 May 2009 00:06:21 +0000 (UTC), Chris Dugan <chrisdotdugan@xxxxxxxxxx>
wrote:

The EEPROM does not loose its contents; the security software in the
radio detects the removal of the permanent 12v feed and goes into code
prompt mode as soon as you apply power again.

Ok - I can see two ways of doing this
1. The radio detects loss of power and asks for a code and compares it with
eeprom contents once only after input. The input code is not stored.
2. The input code is stored in RAM and the radio checks the contents of the RAM
against the EEPROM on every switch-on.

In case 1, the EEPROM could theoretically "fail" and no one would notice until
such time as power was lost and input code requested.
In case 2, an EEPROM fault would cause the comparison to fail and the code would
be requested at switch-on.

In either case if the EEPROM remained faulty it would not be possible to input a
matching code.

All very interesting, but the loss of code is still basically a symptom of power loss. I will note the frequency of occurrence in case it happens on Friday 13th or something. :-)

It's a real pain when it does it on a busy road. No music, Sally Traffic or Sat Nav until I can stop to reset it.
--
Gordon H
Remove "invalid" to reply
.

Relevant Pages

  • Re: Mondeo (III) Radio Code Question
    ... radio detects the removal of the permanent 12v feed and goes into code prompt mode as soon as you apply power again. ... eeprom contents once only after input. ... The input code is stored in RAM and the radio checks the contents of the RAM ...
    (uk.rec.cars.maintenance)
  • Re: EEPROM checksum error
    ... Think about the programming sequence. ... You just assume that the power comes up all at once, ... > I'm guessing your example eeprom wasn't one of these, ... Atmel EEPROM AT25128 is used in the radio. ...
    (sci.electronics.design)
  • Re: EEPROM checksum error
    ... Think about the programming sequence. ... You just assume that the power comes up all at once, ... > I'm guessing your example eeprom wasn't one of these, ... Atmel EEPROM AT25128 is used in the radio. ...
    (sci.electronics.basics)
  • Re: Mondeo (III) Radio Code Question
    ... radio detects the removal of the permanent 12v feed and goes into code ... prompt mode as soon as you apply power again. ... eeprom contents once only after input. ... The input code is stored in RAM and the radio checks the contents of the RAM ...
    (uk.rec.cars.maintenance)
  • Re: EEPROM checksum error
    ... > Atmel EEPROM AT25128 is used in the radio. ... > performaed in the field but EEPROM checksum error did not happen after ... Are you disabling it after each write? ...
    (sci.electronics.design)