Re: JTAG multiple devices

On Aug 24, 5:48 am, Didi <d...@xxxxxxxxxxx> wrote:
I may be missing a major
point and do not understand why is there a plethora of JTAG devices
that are specific to a certain hardware or software.

Because many silicon vendors keep JTAG accessible hardware on their
chips which goes beyond boundary scan secret; then, they give the
data some "firm" which is allowed to collect a few thousands per
sold cable - or do it themselves. The cash they collect on that
is negligible, but once you give in they have you under control.
An astonishingly low number of people seem to object paying
ransoms like that.

Yes, we object. Especially when we need a few hundred production
testers and programmers. We don't need stinking Window Point and
Click either (make no sense in production environments), just connect
and power it up. We spent hundreds of hours on development (to save
hundreds of hours in production), but it would still be cheaper
overall. We make the custom device for less than $10 each.

If you can do all you need via boundary scan only, though,
there should be some cheap way to do it - open source or
whatever. (I cannot name any because the tols I use have been
written here and run under DPS which you don't have).

Following Atmel specs, we could SPI program the AVR and JTAG boundary
scan them. We are unable to do JTAG programming as stated in the AVR
specs. So, we end up with both interfaces on every production board.




.

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