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what flash memory is used in Subaru Denso ECU ?

PostPosted: Fri Sep 21, 2007 12:52 am
by hmanxx
Hi,
I am trying to hunt for flash memory used in Subaru Denso ECU..anyone has any idea..the reason is I want to read the maximum write cycle spec ..

Reading Intel Satra flash, if using 12V to flash..getting around 1000 cycles..but use low voltage at 3.3V..can go beyond 10K cyclces.

PostPosted: Fri Sep 21, 2007 8:53 am
by Freon
The flash memory is integrated into the chip on both the HC16 and SH-2 CPU chip. I know the SH-2 docs say it is good for 100 reflashes, but experimentally people have gone well over this (350+).

I've never seen a convincing report or claim that someone has flashed their ECU to the point of failure.

PostPosted: Thu Sep 27, 2007 7:42 am
by hmanxx
HC16 with 192K memory..is feasible to integrate the memory however for the SH2 with 1MB ? this is abit out of whack..

Doing it this way just taking way too much silicon on the SH2..damn funny planning.

PostPosted: Thu Sep 27, 2007 10:32 am
by Freon
Why do you say that? You can get 4 *gigabytes* of flash memory on a key fob that is about the total size of the 7055/7058 package (it's not a small chip). The actual flash memor chip in the keyfob is waaaay smaller than a 7055/7058.

PostPosted: Sun Oct 14, 2007 9:21 am
by hmanxx
what is key fob ? I was abit confuse..will putting the flash into the ASIC incurred more silicon real estate and cost much more than getting a off the shelf flash chip.

I used to face this problem on ASIC budget planning.. May be automobile industries have high profit margin and can put convenient as priority and dont care on cost.

PostPosted: Sun Oct 14, 2007 12:01 pm
by Freon
A USB keyfob with flash memory? Certainly you've seen one of these! They're about the size of a pack of gum and can hold up to 4 gigabytes using flash memory. SD memory for cameras, memory sticks...

I can't see why it is surprising that a rather large chip like the 7055 or even HC16 can hold one megabyte when cheap consumer devices with smaller footprint can hold four thousand (4,000) times more for under $40.

http://en.wikipedia.org/wiki/USB_flash_drive

PostPosted: Sun Oct 14, 2007 3:49 pm
by radsdau
Then again, USB drives use NAND flash and the micros with built-in memory use NOR flash; the implementation is less flexible in NAND flash-based devices (block based rather than random access read/write), but the tradeoff is that the density is *far* higher.
http://en.wikipedia.org/wiki/Flash_memory
That's my understanding of it anyway.