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Calculate timer values

tags/v3.0
Olaf Rempel 9 months ago
parent
commit
7e7e50ad84
1 changed files with 8 additions and 7 deletions
  1. +8
    -7
      main.c

+ 8
- 7
main.c View File

@@ -25,11 +25,13 @@
#define EEPROM_SUPPORT 1
#define LED_SUPPORT 1

/* 25ms @8MHz */
#define TIMER_RELOAD (0xFF - 195)
#define F_CPU 8000000ULL
#define TIMER_DIVISOR 1024
#define TIMER_IRQFREQ_MS 25
#define TIMEOUT_MS 1000

/* 40 * 25ms */
#define TIMEOUT 40
#define TIMER_MSEC2TICKS(x) ((x * F_CPU) / (TIMER_DIVISOR * 1000ULL))
#define TIMER_MSEC2IRQCNT(x) (x / TIMER_IRQFREQ_MS)

#if LED_SUPPORT
#define LED_INIT() DDRB = ((1<<PORTB4) | (1<<PORTB5))
@@ -130,8 +132,7 @@ const static uint8_t chipinfo[8] = {
#endif
};

/* wait 40 * 25ms = 1s */
static uint8_t boot_timeout = TIMEOUT;
static uint8_t boot_timeout = TIMER_MSEC2IRQCNT(TIMEOUT_MS);
static uint8_t cmd = CMD_WAIT;

/* flash buffer */
@@ -413,7 +414,7 @@ static void TWI_vect(void)
static void TIMER0_OVF_vect(void)
{
/* restart timer */
TCNT0 = TIMER_RELOAD;
TCNT0 = 0xFF - TIMER_MSEC2TICKS(TIMER_IRQFREQ_MS);

/* blink LED while running */
LED_GN_TOGGLE();


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