ISR in einer anderen ISR

tue_was()

isr1()
{
 tue_was()
}

isr2()
{
 123
}

tue_was()
{
 enable isr2()
  tue was anderes
 disable isr2()
}

So nach dem Prinzip hab ich das Ganze.
Und leider funkt es noch nciht, bin noch am nachforschen.

Geht wenn man die <u> Dinger entfernt.
Hier der Text:

Nested interrupts

The AVR hardware clears the global interrupt flag in SREG before
entering an interrupt vector. Thus, normally interrupts will remain
disabled inside the handler until the handler exits, where the RETI
instruction (that is emitted by the compiler as part of the normal
function epilogue for an interrupt handler) will eventually re-enable
further interrupts. For that reason, interrupt handlers normally do not
nest. For most interrupt handlers, this is the desired behaviour, for
some it is even required in order to prevent infinitely recursive
interrupts (like UART interrupts, or level-triggered external
interrupts). In rare circumstances though it might be desired to
re-enable the global interrupt flag as early as possible in the
interrupt handler, in order to not defer any other interrupt more than
absolutely needed. This could be done using an sei() instruction right
at the beginning of the interrupt handler, but this still leaves few
instructions inside the compiler-generated function prologue to run
with global interrupts disabled. The compiler can be instructed to
insert an SEI instruction right at the beginning of an interrupt
handler by declaring the handler the following way:

void XXX_vect(void) __attribute__((interrupt));
void XXX_vect(void) {
  ...
}

where XXX_vect is the name of a valid interrupt vector for the MCU type
in question, as explained below.

--------------------------------------------------------------------

Und das hab ich auch getestet gehabt

void USART_IR_NAME_vect(void) __attribute__((interrupt));
void USART_IR_NAME_vect(void)
{
  weitere Funktion in der TImer IR erlaubt wird
}


Und irgendwas klappt da nicht.