Pins A1/A2 uses TC4 to generate PWM, the same used in Servo library,
so both cannot work together.

The attribute ATTR_ANALOG is needed to select DAC, so it has been
removed from pins A1..A5 that doesn't have a DAC.

The selection of the correct timer peripheral is now
decided through the PIN_ATTR_{TIMER/TIMER_ALT} attribute.

See #30

Now PA14 is connected to Arduino Zero digital pin 2(NO-PWM) and PA08 is connected to digial pin 4(PWM)
Also connected PA13 to Arduino Zero ATN pin

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

variant.c instead of TC/TCC information

- Update test.cpp
- Add support of wiring_analog.c in AS6 test project
- Modify variant for PWM generation on LED (pin 13)