Re: [avr-gcc-list] using UART to send from within SIGNAL(SIG_UART_RECV) function

[Joerg Wunsch]

As Christoph Plattner wrote:

> No, in general, the idea is not bad !
> IMO it is necessary to give a transmitt character to the UART to send,
> for example to implement XON/XOFF !

But then, you need a buffered transmitter.  Otherwise, you cannot
guarantee that the Rx interrupt service would not block indefinately
long (well, at the usual 9600 Bd, i'd consider 1 ms to flush the
hardware Tx buffer as `indefinately').

If you've got a memory-buffered UART handling, then you just put the
Xon/Xoff character into the queue, and can immediately return from Rx
interrupt.

> Bad design is, to do a busy waiting.

Unless you've got a memory-buffered UART driver, you cannot guarantee
to avoid busy waiting.
-- 
J"org Wunsch                                           Unix support engineer
address@hidden        http://www.interface-systems.de/~j/
avr-gcc-list at http://avr1.org