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update ex02 comments

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hugo LAMY
2025-03-06 12:33:32 +01:00
parent 9398b623af
commit 25541d0582
1 changed files with 25 additions and 25 deletions
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50
module01/ex02/main.c
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@@ -1,36 +1,36 @@
#include <avr/io.h> #include <avr/io.h>
// stringify // stringify
#define STRINGIFY_HELPER(x) #x #define STRINGIFY_HELPER(x) #x
#define STRINGIFY(x) STRINGIFY_HELPER(x) #define STRINGIFY(x) STRINGIFY_HELPER(x)
// concatenate // concatenate
#define CONCAT_HELPER(x, y) x ## y #define CONCAT_HELPER(x, y) x ## y
#define CONCAT(x, y) CONCAT_HELPER(x, y) #define CONCAT(x, y) CONCAT_HELPER(x, y)
// get argument // get argument
#define ARG_1(v1, v2) v1 #define ARG_1(v1, v2) v1
#define ARG_2(v1, v2) v2 #define ARG_2(v1, v2) v2
#define GET_PORT(args) ARG_1 args #define GET_PORT(args) ARG_1 args
#define GET_BIT(args) ARG_2 args #define GET_BIT(args) ARG_2 args
// actions on registers // actions on registers
#define SET(register, bit) register |= 1 << bit #define SET(register, bit) register |= 1 << bit
#define CLEAR(register, bit) register &= ~(1 << bit) #define CLEAR(register, bit) register &= ~(1 << bit)
#define TEST(register, bit) register & 1 << bit #define TEST(register, bit) register & 1 << bit
#define TOGGLE(register, bit) register ^= 1 << bit #define TOGGLE(register, bit) register ^= 1 << bit
// actions on elements // actions on elements
#define SET_ELEM(elem) SET(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem)) #define SET_ELEM(elem) SET(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
#define CLEAR_ELEM(elem) CLEAR(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem)) #define CLEAR_ELEM(elem) CLEAR(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
#define TEST_ELEM(elem) TEST(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem)) #define TEST_ELEM(elem) TEST(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
#define TOGGLE_ELEM(elem) TOGGLE(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem)) #define TOGGLE_ELEM(elem) TOGGLE(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
#define MODE_OUTPUT(elem) SET(CONCAT(DDR, GET_PORT(elem)), GET_BIT(elem)) #define MODE_OUTPUT(elem) SET(CONCAT(DDR, GET_PORT(elem)), GET_BIT(elem))
#define MODE_INPUT(elem) CLEAR(CONCAT(DDR, GET_PORT(elem)), GET_BIT(elem)) #define MODE_INPUT(elem) CLEAR(CONCAT(DDR, GET_PORT(elem)), GET_BIT(elem))
#define TOGGLE_PIN(elem) SET(CONCAT(PIN, GET_PORT(elem)), GET_BIT(elem)) #define TOGGLE_PIN(elem) SET(CONCAT(PIN, GET_PORT(elem)), GET_BIT(elem))
#define TEST_PIN(elem) (TEST(CONCAT(PIN, GET_PORT(elem)), GET_BIT(elem))) #define TEST_PIN(elem) (TEST(CONCAT(PIN, GET_PORT(elem)), GET_BIT(elem)))
#define IS_PIN_SET(elem) (TEST_PIN(elem) == 0) #define IS_PIN_SET(elem) (TEST_PIN(elem) == 0)
#define IS_PIN_CLEAR(elem) (TEST_PIN(elem) == 1) #define IS_PIN_CLEAR(elem) (TEST_PIN(elem) == 1)
// bits // bits
#define D1 0 #define D1 0
@@ -76,13 +76,13 @@ int main() {
SET(TCCR1B, WGM12); SET(TCCR1B, WGM12);
SET(TCCR1B, WGM13); SET(TCCR1B, WGM13);
// 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) // 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)
SET(TCCR1A, COM1A1); SET(TCCR1A, COM1A1);
// set the period (compare TOP value) // Table 16-4 : set the period (compare TOP value)
ICR1 = TIME_MS(PERIOD); ICR1 = TIME_MS(PERIOD);
// set the duty cycle to DUTY_CYCLE% of the time // 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
OCR1A = TIME_MS(DUTY_CYCLE); OCR1A = TIME_MS(DUTY_CYCLE);
// start the timer with the prescaler // start the timer with the prescaler