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Reprogramming a uC FLASH while running code - STM32F

Discussion in 'Embedded' started by John-Smith, May 10, 2014.

  1. John-Smith

    John-Smith Guest

    If your product sells for reasonable money (say $200 or more) the
    ability to update the firmware in the field is a vital safeguard
    against a major bug, which would otherwise result in a huge recall,
    loads of warranty claims, and if you are selling to any big-company
    customer/reseller or through a big distributor, they will bend you
    over a barrel and shaft you and make you absolutely pay for the
    mistake in blood.

    That could trash your business totally if you are a small company.

    We sell to a US based $20BN company, for example, and they are packed
    with the usual corporate brown-nosers and political climbers, and the
    best way to crawl up their internal ladder is to scalp one of the
    company's suppliers. So we need to be very very careful.

    A USB interface is handy for firmware upgrades - even if it is
    disabled in all normal operating contexts.

    If the product has say wifi then it can download the update all by
    itself (obviously after the customer has consented and performed some
    enabling actions) and that's even better, because it further reduces
    the % of returns if you have made some mistake. It could make a
    difference between the reseller shafting you by returning his entire
    stock to you (at *your* expense, all the way from say the USA back to
    Europe) just to make a point, and accepting that the in the field
    upgrade is a reasonable solution.

    I am in a business where our best selling product has 1995 firmware
    and nobody has yet found a bug, but you can never be sure :)

    The ST 32-bit ARM micros are pretty amazing. I have just found they do
    a little 6mm x 6mm one, with 16k of code space and 4k of RAM, for
    $1.50. If it wasn't for the higher power consumption, few would bother
    using the little Atmel or PIC devices. One can span a huge product
    range with the same device family and crucially the same development
    tools and same expertise. We still use the AT90S1200 (last time buy
    was a few years ago but we still have stock) and the last 1 or 2
    replacements like the 2313 have already been discontinued (Atmel seem
    to move on quite quickly these days, sadly, and yes I saw they do ARM
    processors too) but they are about $1 (10k).

    I am looking at the $10 32F with 1MB FLASH.
    John-Smith, May 13, 2014
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  2. John-Smith

    krw Guest

    You can't change anything in your product line? You must not use many
    semiconductor components (certainly no LSI).
    krw, May 14, 2014
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  3. John-Smith

    Paul Guest

    You would be amazed how many companies in Aviation and other industries
    have large stocks of old wafers and packaged devices in nitogen filled
    packaging and temperature controlled storage.

    Changes can be made but the effort to do so is VERY VERY expensive.

    Paul Carpenter |
    <http://www.pcserviceselectronics.co.uk/> PC Services
    <http://www.pcserviceselectronics.co.uk/pi/> Raspberry Pi Add-ons
    <http://www.pcserviceselectronics.co.uk/fonts/> Timing Diagram Font
    <http://www.badweb.org.uk/> For those web sites you hate
    Paul, May 14, 2014
  4. John-Smith

    John-Smith Guest

    Actually aviation is my "other" hobby so I know quite a lot about that

    I think the main reason they don't change stuff is because there is so
    little interesting R&D work in that business (they run their cash cows
    for a decade or more if they can) that anybody with more than 2
    braincells leaves pretty quick, and they have no way to fix anything.

    John-Smith, May 14, 2014
  5. John-Smith

    Paul Guest

    A decade in aviation is a flash in the pan.

    A lot of aircraft take 5-10 years to develop, test, certify....... Then
    have service lifetime (or product lifetime) of 20-30 years. then some
    are still flying many decades later, doubt a lot of the newer ones will

    In one case a device was respun 2 times as ASIC due to process changes
    before certification, aircraft is in service now, and they have recently
    bought the last batch of their 'last time buy' to keep them going for 20
    years. These are all now in special storage.

    The design uses an EEPROM that want EOL something like 12 years ago
    and they bought a last time buy of wafers for that. I believe they had
    them packaged before that became a problem. The high temp ceramic
    packaging is oddball to say the least, and the crystal is in some 64 pin

    When any new batch of wafers were made for ASIC in question, a tested
    sample batch was sent to do at least 100 hours aircraft flight time
    before the wafers could be probed, packaged, tested...

    So for one aircraft there is a lot of devices in storage to last 20
    years of production.

    Aviation, Transport have long life cycles and you dont upgrade unless
    you have to.

    Medical can be longer still, once had call about a medical scanner back
    in 2002. I asked how old was the scanner, their reply was -

    "The earliest record we can find is when it moved to the NEW
    building in 1968"

    Paul Carpenter |
    <http://www.pcserviceselectronics.co.uk/> PC Services
    <http://www.pcserviceselectronics.co.uk/pi/> Raspberry Pi Add-ons
    <http://www.pcserviceselectronics.co.uk/fonts/> Timing Diagram Font
    <http://www.badweb.org.uk/> For those web sites you hate
    Paul, May 15, 2014
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