programming 101 and checksum

[Vance Rose]

At 02:51 PM 8/9/98 -0600, you wrote:
>Vance Rose wrote:
>> 
>> At 07:01 AM 8/9/98 -0400, you wrote:
>> >
>> >-----Original Message-----
>> >From: Shannen Durphey <Shannen at mcn.net>
>> >To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
>> >Date: Sunday, August 09, 1998 3:13 AM
>> >Subject: programming 101 and checksum
>> >
>> >
>> >>Memory location 0x004 is listed as the checksum enable for
>> >>7747 ecm. This value is $42 in my factory files.  Does
>> >>anyone know what the value is to disable checksum?
>> >
>> >AA
>> >
>> > Also,
>> >>this location in 8747 ecm contains the value $4F.  Is it
>> >>safe to assume this is checksum enable for this ecm?
>> >
>> >I don't know, could try a chip with AA entry and see
>> >
>> >Bruce
>> >
>> >>Thanks
>> >>
>> >>Shannen
>> >>
>> >
>> >Hi All
>> 
>>         If ya have time - just disassemble code. The checksum is usually
early in
>> program section. Being a novice it was one of my first finds for 165 ecm.
>> 
>> Vance
>
>Ummm, you make it sound so easy, I wish I knew what you
>meant.  I've looked at disassembled code on Ludis' site, and
>it's pretty much Greek to me.  So where's a guy to go to
>learn more?
>
>Shannen
>
>Hi Shannen

	Easy - nooo!! If your learning it's actaully vverry boring. Kinda like
watching paint dry. Have to really want to do the work. In my file have
only commented about 20 pages, about 145 to finish that one file. Do that
work in winter evening when rhere is nothing else to tinker with. 

	A good start would be the pink motorola book for 68hc11. There has been
recent post about source for it.

Vance