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Fix for counter overflow in delays based on sdk_system_get_time()

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This commit is contained in:
UncleRus 2017-04-21 17:53:13 +05:00
parent b3f658bdbf
commit 55e08de21c
3 changed files with 23 additions and 16 deletions
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10
extras/ultrasonic/ultrasonic.c
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@ -15,6 +15,8 @@
#define PING_TIMEOUT 6000
#define ROUNDTRIP 58
#define timeout_expired(start, len) ((uint32_t)(sdk_system_get_time() - (start)) >= (len))
void ultrasoinc_init(const ultrasonic_sensor_t *dev)
{
gpio_enable(dev->trigger_pin, GPIO_OUTPUT);
@ -36,21 +38,21 @@ int32_t ultrasoinc_measure_cm(const ultrasonic_sensor_t *dev, uint32_t max_dista
return ULTRASONIC_ERROR_PING;
// Wait for echo
uint32_t timeout = sdk_system_get_time() + PING_TIMEOUT;
uint32_t start = sdk_system_get_time();
while (!gpio_read(dev->echo_pin))
{
if (sdk_system_get_time() >= timeout)
if (timeout_expired(start, PING_TIMEOUT))
return ULTRASONIC_ERROR_PING_TIMEOUT;
}
// got echo, measuring
uint32_t echo_start = sdk_system_get_time();
uint32_t time = echo_start;
timeout = echo_start + max_distance * ROUNDTRIP;
uint32_t meas_timeout = echo_start + max_distance * ROUNDTRIP;
while (gpio_read(dev->echo_pin))
{
time = sdk_system_get_time();
if (time >= timeout)
if (timeout_expired(echo_start, meas_timeout))
return ULTRASONIC_ERROR_ECHO_TIMEOUT;
}