Hardware init function profit a great deal from being inlined if the
given parameters are constant -- which is the common use-case, we could
probably call this for all timers and still have less overhead. The
hwtimer_pwm_ini (which calls hwtimer_ini) gets completely computed at
compile-time resulting only in the register settings of hwtimer_ini.
This is now possible because we get rid of static storage for the
max_ticks and instead compute this in hwtimer_pwm_max_ticks from the
timer register settings.
Some platforms are missing timer channels, this is now left to the
(missing) preprocessor definitions on those platforms, no
platform-specific defines needed anymore.
Also fix usage of timer counter register 3 (hardcoded) in
cpu/avr/dev/clock.c -- this code isn't used on many platforms as it
requires a very special quartz clock frequency but this now also uses
the platform timer specification.
We can now directly compile arduino sketches (.pde) files.
Arduino compatible analogWrite works now.
But there is still a long way to go, serial I/O and timer stuff (delay,
millis etc) currently don't work (not tested but I don't expect this to
work).
It can be used in an arduino sketch or in a normal contiki program.
We get a PWM frequency of 490.2 Hz (a period of 2.040 ms), that's
Arduino compatible. If you need different frequencies see native timer
usage in examples/osd/pwm-example
In a contiki program you have to call arduino_pwm_timer_init to
initialize the timer before pwm works. The arduino sketch wrapper
already does this.
For running a sketch, see examples/osd/arduino-sketch
Since avr-libc 1.8.0 MCUSR is marked as poison as it was replaced by the
correct name MCUCSR.
Thus code still using the old MCUSR name does not compile anymore.
This commit replaces usages of former MCUSR by its new name MCUCSR and
modifies the alias fallback accordingly.
The border-router tries to transmit and do other stuff after turning
the radio off, and the radio driver didn't handle that very well.
With this fix, it's no longer necessary to reset the border router
after starting tunslip6.
The previous chip detection was inspired by the old IP65 driver code. For some reason it didn't work as expected. The new code is simpler and based on this statement in the chip datasheet: "The upper byte always reads as 33h and can be used to help determine the I/O location of the LAN91C96."
The problem with the current version of the code was that the condition at the end of the do...while loop at Timer A1 interrupt:
while((TACCR1 - TAR) > INTERVAL);
evaluates to false whenever TACCR1 == TAR.
Not incrementing TACCR1 in this case leads to Timer A1 interrupt not being called for 2 seconds, until TAR counter reaches TACCR1 again after an overflow.
The patch avoids this problem by changing the condition of the loop, and using CLOCK_LT macro to compare between time values.
The patch also attempts to fix another problem: a read of TAR register while it is being updated may return a lower value than the actual contents. To avoid that, the "read twice and compare results" idiom should be used. As the TAR register is updated by the actual hardware, it is of no importance whether it is read with interrupts disabled or enabled; the problem can occur in both contexts.
