update ex02 comments
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@@ -1,36 +1,36 @@
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#include <avr/io.h>
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// stringify
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#define STRINGIFY_HELPER(x) #x
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#define STRINGIFY(x) STRINGIFY_HELPER(x)
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#define STRINGIFY_HELPER(x) #x
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#define STRINGIFY(x) STRINGIFY_HELPER(x)
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// concatenate
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#define CONCAT_HELPER(x, y) x ## y
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#define CONCAT(x, y) CONCAT_HELPER(x, y)
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#define CONCAT_HELPER(x, y) x ## y
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#define CONCAT(x, y) CONCAT_HELPER(x, y)
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// get argument
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#define ARG_1(v1, v2) v1
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#define ARG_2(v1, v2) v2
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#define GET_PORT(args) ARG_1 args
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#define GET_BIT(args) ARG_2 args
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#define ARG_1(v1, v2) v1
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#define ARG_2(v1, v2) v2
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#define GET_PORT(args) ARG_1 args
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#define GET_BIT(args) ARG_2 args
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// actions on registers
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#define SET(register, bit) register |= 1 << bit
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#define CLEAR(register, bit) register &= ~(1 << bit)
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#define TEST(register, bit) register & 1 << bit
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#define TOGGLE(register, bit) register ^= 1 << bit
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#define SET(register, bit) register |= 1 << bit
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#define CLEAR(register, bit) register &= ~(1 << bit)
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#define TEST(register, bit) register & 1 << bit
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#define TOGGLE(register, bit) register ^= 1 << bit
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// actions on elements
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#define SET_ELEM(elem) SET(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
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#define CLEAR_ELEM(elem) CLEAR(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
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#define TEST_ELEM(elem) TEST(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
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#define TOGGLE_ELEM(elem) TOGGLE(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
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#define MODE_OUTPUT(elem) SET(CONCAT(DDR, GET_PORT(elem)), GET_BIT(elem))
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#define MODE_INPUT(elem) CLEAR(CONCAT(DDR, GET_PORT(elem)), GET_BIT(elem))
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#define TOGGLE_PIN(elem) SET(CONCAT(PIN, GET_PORT(elem)), GET_BIT(elem))
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#define TEST_PIN(elem) (TEST(CONCAT(PIN, GET_PORT(elem)), GET_BIT(elem)))
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#define IS_PIN_SET(elem) (TEST_PIN(elem) == 0)
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#define IS_PIN_CLEAR(elem) (TEST_PIN(elem) == 1)
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#define SET_ELEM(elem) SET(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
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#define CLEAR_ELEM(elem) CLEAR(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
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#define TEST_ELEM(elem) TEST(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
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#define TOGGLE_ELEM(elem) TOGGLE(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
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#define MODE_OUTPUT(elem) SET(CONCAT(DDR, GET_PORT(elem)), GET_BIT(elem))
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#define MODE_INPUT(elem) CLEAR(CONCAT(DDR, GET_PORT(elem)), GET_BIT(elem))
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#define TOGGLE_PIN(elem) SET(CONCAT(PIN, GET_PORT(elem)), GET_BIT(elem))
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#define TEST_PIN(elem) (TEST(CONCAT(PIN, GET_PORT(elem)), GET_BIT(elem)))
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#define IS_PIN_SET(elem) (TEST_PIN(elem) == 0)
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#define IS_PIN_CLEAR(elem) (TEST_PIN(elem) == 1)
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// bits
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#define D1 0
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@@ -76,13 +76,13 @@ int main() {
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SET(TCCR1B, WGM12);
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SET(TCCR1B, WGM13);
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// Table 16-2 : Non-inverting mode, the LED will be ON for DUTY_CYCLE% of the time (CLEAR OC1A on compare match, SET OC1A at BOTTOM)
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// Table 16-2 : non-inverting mode, the LED will be ON for DUTY_CYCLE% of the time (CLEAR OC1A on compare match, SET OC1A at BOTTOM)
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SET(TCCR1A, COM1A1);
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// set the period (compare TOP value)
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// Table 16-4 : set the period (compare TOP value)
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ICR1 = TIME_MS(PERIOD);
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// set the duty cycle to DUTY_CYCLE% of the time
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// 16.9.3 : set the duty cycle to DUTY_CYCLE% of the time -> OC1A (alternate function of PORTB1, aka LED2) is cleared when TCNT1 (the counter value) equals OCR1A
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OCR1A = TIME_MS(DUTY_CYCLE);
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// start the timer with the prescaler
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