View Single Post
Old 01-01-2009, 02:43 AM   #73 (permalink)
Moderate your Moderation.
Join Date: Nov 2008
Location: Troy, Pa.
Posts: 8,919

Pasta - '96 Volkswagen Passat TDi
90 day: 45.22 mpg (US)
Thanks: 1,369
Thanked 430 Times in 353 Posts
You said that you have alot of space available on the chip, right?

Get a binary switch, and write two diff programs to two cells on the same chip... like if you have a 512 chip, write 2x256 to it. This will allow you to flash one sector of the memory while still running on another sector, then switch them over at your next stop sign by flipping the binary switch, so you can flash/update the first sector, etc.

Another way to do this is with sister stacks. You get a daughter board and put 2 or 4 or 8 sockets on it, each one using a chip that holds one ROM. Use a standard multi-position switch to power each chip individually.. the sister stack will always only have one chip powered, and the only memory that will be used is the powered chip.

It's a Honda thing.. lots of guys used to use dual-map ECUs on a binary switch, one tuned for street and one tuned for racing.

EEPROM - Electronically Erase-able/Programmable Read Only Memory.

I assume that means you can't actually flash it w/o disrupting the controller. UNLESS - If you shadowed the EEPROM memory, so that the controller would read the memory from a static EEPROM on startup, but xfer it to a RAM setup, you could do two things - Edit the RAM setup OTF, probably in hex or something similar, without flashing the whole program, and you'd be able to flash the EEPROM and reload it to RAM w/o disrupting the operation of the controller.

This is what things like the Banks Six Shooter and BullyDog eeprom piggy-back devices do - they edit the signal in the ECU on the fly by taking input/output information into account, then giving the RAM (operating memory) what it "needs" to see to achieve the goal at hand.

In shorter form - the ECU boots up, copies memory from EEPROM to RAM, runs from RAM.

You can edit RAM on the fly, since this is what sensors do anyway. You can edit/flash EEPROM and re-load RAM on the fly without disruption.

Although your acceleration ramp might be an issue, since you'll be effectively resetting the system when you reload the EEPROM into RAM. Then again, the ramp only applies to WOT, right? So let off the pedal when you hit the button, count 1 or 3 seconds off, then "gas" it again.
"ʞɐǝɹɟ ɐ ǝɹ,noʎ uǝɥʍ 'ʇı ʇ,usı 'ʎlǝuol s,ʇı"

  Reply With Quote
The Following User Says Thank You to Christ For This Useful Post:
faerietree (07-14-2012)