Re: [avr-gcc-list] when is it safe to use -mtiny-stack

[Joerg Wunsch]

John Regehr <address@hidden> wrote:

> Is it not sufficient for the maximum extent of the stack to be 256
> bytes?

Only if the stack starts at a 0xXXFF address.  As RAMEND on the
ATmega3290 is equal 0x8FF, this is by default the case on that MCU
type.  Other MCU types (in particular older AVRs) have a RAMEND of
e.g. 0x25F.  In that case, the stack could only extend to 0x60 bytes
before changing SPH were due.  (Alternatively, the stack could be
relocated to a lower address, e.g. 0x1FF.)

-- 
cheers, J"org               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/                        NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)