Re: Atmel AVR development tools

On Feb 1, 8:10 am, Vladimir Vassilevsky <antispam_bo...@xxxxxxxxxxx>
wrote:
dbvanhorn wrote:
The AVR debug core is unreliable, jtag or non-jtag. SPI programming
is much more reliable. Also, avoid bootloaders.

I keep hoping it's something I'm doing. That's fixable, I just need to
know what to do/not do .

Interesting comment re bootloaders, why do you say that?

The AVR bootloader has to contain the subroutines for erasing and
programming. Those subroutines can be activated accidentally by an
electric glitch, software bug, cosmic ray, unholy spirit or something
like that. Although this event is not very likely, I have observed the
failure rate due to that at the order of one per 5k units per year in
the harsh EMI environment.

Very often, the bootloader does not boot. I have tried serial and usb
boot loaders. They just stop working suddenly. I can still erase and
reflash the chip with spi. Same thing with jtag debugging. Jtag
would fail to response, but spi always work.

AVR runtime core and spi programming is the only thing I trust.
Otherwise, i would be looking for another uC.


The safer approach would be loading the subroutines to RAM from the
outside only when you need to reflash the device. However this can't be
done with the AVR.

Yes, the biggest weakness of the AVR is accessibility of the sram from
spi.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultanthttp://www.abvolt.com

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Relevant Pages

  • [PATCH] SPI: add spi_butterfly driver
    ... This adds a bitbanging parport based adaptor cable for AVR Butterfly, ... SPI links to its DataFlash chip and firmware running in the card. ...
    (Linux-Kernel)
  • [patch 2.6.14-rc6-git 6/6] SPI parport adapter to AVR Butterfly
    ... This patch ties together a lot of things; it lets folk with PCs use SPI ... etc) that can use the same adapter to update firmware. ... This adds a bitbanging parport based adaptor cable for AVR Butterfly, givingSPI links to its DataFlash chip and firmware running in the card. ...
    (Linux-Kernel)
  • Re: ATmega SPI question
    ... therefore AVR is not able to ... That's why i'm seeking about Master SPI mode with AVR. ... > I use the Mega16 as a slave on an SPI line. ... > next transmit data byte into the transmitter register. ...
    (comp.arch.embedded)
  • Re: ATmega SPI question
    ... > Supposing AVR is a configured as a Master SPI device. ... > Is it possible to discard AVR master SCK output signal and make SCK as an ... > My app is connecting a Quad voice A/MU law Codec to an AVR SPI ...
    (comp.arch.embedded)
  • Re: ATmega SPI question
    ... >> Configuring SPI bus in slave mode may require one more signal to drive SS. ... AVR is configured as a slave. ... That's why i'm seeking about Master SPI mode with AVR. ...
    (comp.arch.embedded)