what flash memory is used in Subaru Denso ECU ?

Developer topics relating to hardware that interfaces PCs to ECUs

Moderator: Freon

what flash memory is used in Subaru Denso ECU ?

Postby hmanxx » Fri Sep 21, 2007 12:52 am

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.
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Postby Freon » Fri Sep 21, 2007 8:53 am

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.
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Postby hmanxx » Thu Sep 27, 2007 7:42 am

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.
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Postby Freon » Thu Sep 27, 2007 10:32 am

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.
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Postby hmanxx » Sun Oct 14, 2007 9:21 am

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.
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Postby Freon » Sun Oct 14, 2007 12:01 pm

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
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Postby radsdau » Sun Oct 14, 2007 3:49 pm

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.
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