[Diy_efi] Factory turbo motorcycle reverse engineering project

[Adam Wade]

Well, I am working on developing chips for the Honda
CX500 Turbo and hopefully the CX650 Turbo as well.

Here's what I have so far:

"As I surmised in an earlier post, the CX500T unit had
a 8xxx MPU of some sort as the box used the 8253 PIT,
which is used with the 8xxx family. Futher
investigation of the pinouts leads me to believe the
MCU is in the 8035/39/40 sub-family. Nipondenso is
large enought to fab their own chips, but I think they
only "branded" the available chip with their
number...ND079753-0021. I tried to read on-board ROM
as an 8048/49, but got nothing in the read buffer. The
8035 units are CPU only with no memory on-board. All
these chips use the same pinout.  The companion chip
is a 8755.  The 2716 eeprom is standard."

I have hex dumps of both the 2716 and the 8755.  I am
trying to sort out which maps are where, and to
disassemble the machine code, as there is an overboost
fuel cut-off I wish to eliminate.

If I can't get it sorted to where I can burn my own
chip, I may just build a Megasquirt.  But since I can
socket the EPROM, it makes more sense to me to just do
tabletop work and save my money and testing effort. 
:)  I have access to a step-testing eddy current dyno,
as well as an attached four-gas analyzer and an
emulator, so once I get the code and the maps sussed,
tuning and burning a replacement chip will be simple
and easy.

Old-tech wizards, I'm looking forward to hearing from
you.  :)

=====
| 82 Honda CX500 Turbo (Cassandra)  90 Kwak Zephyr 550 (Daphne) |
| "It was like an emergency ward after a great catastrophe; it  |
|   didn't matter what race or class the victims belonged to.   |
|  They were all given the same miracle drug, which was coffee. |
|   The catastrophe in this case, of course, was that the sun   |
|     had come up again."                    -Kurt Vonnegut     |
|   Buy my M/C Fuel Inj. Handbook  -  http://tinyurl.com/2e8eu  |


	
		
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