[avrdude-dev] [bug #30844] attiny45 + arduino programmer won't verify

[Joerg Wunsch]

Follow-up Comment #3, bug #30844 (project avrdude):

I'm sorry, I'm afraid the fault is within your programmer's STK500
implementation.  The only difference between the two files is that
when pretending an ATtiny25, only half the pagesize is used both,
during initialization as well as within the Cmnd_STK_PROG_PAGE
commands.  The page sizes used are correct with respect to the
device's datasheet though, so it's even more surprising that
pretending the device to be an ATtiny25 does actually work at all
(page programming there is started with only half the data of an
actual flash page).

There is one flaw in the entire protocol, this is the so-called
"devicecode".  The Atmel appnote AVR061 (which describes the v1.x
STK500 protocol) mentions that this code were according to the file
"devices.h", but as this protocol version has been discontinued years
ago, the most recent AVRs mentioned in the file are the ATmega169 and
ATmega128, respectively.  (The file dates 2002-09-09.)  So, for those
who still wish to use STK500v1 for whatever reason, avrdude.conf has
to invent a "devicecode" of its own, which is 0x14 for both, the
ATtiny25 as well as the ATtiny45.  Maybe your programmer is stumbling
across that?  Normally, I'd expect any sane programmer implementation
to simply ignore that value these days.


    _______________________________________________________

Reply to this item at:

  <http://savannah.nongnu.org/bugs/?30844>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.nongnu.org/