[En-Nut-Discussion] AT90CAN128 issues have been confirmed to be a bug on the chip

[Henrik Maier]

Hello fellow AT90CAN128 users and AT90CAN128 users-to-be,

Refer to earlier posts in thread "Status of CAN128 Port?" where I am 
describing issues when porting Nut/OS to the AT90CAN128 chip.

Atmel now has officially confirmed the bug and the issues I experienced 
with Nut/OS are related to this bug on the silicon.

What I cannot believe is that I had to be the first one discovering this 
bug as I could not find any reference to it in any of the AVR related 
forums.

Until an official Errata is published, please refer to the following bug 
description:

---[snip]-------------------------------------
Hello Mr Maier,

I confirm the bug on our Product AT90CAN128.
The following description will be added in the next version of the
datasheet.
-------------------------------------------
Miss-functioning when code stack is in XRAM
If either an "IN" or an "OUT" instruction is executed just before an
interrupt occurs and if the stack pointer (SP) targets the XRAM, the
instruction is
executed twice. Because the other instructions are not from the same
class,
it seems that only "IN" and "OUT" instructions are concerned.

Problem Fix/Workaround
Map the code stack in SRAM.
-------------------------------------------
We confirm that the only workaround is to map the stack in the internal
RAM.

The Design correction will be done as soon as possible.

Technical Marketing
Atmel - Nantes - France
---[snip]-------------------------------------


Regards

Henrik

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