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drivers/sht3x: use crc8 function from common code

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This makes the sht3x driver use the crc-8 routine from sys/hashes.
It's the same code, was just moved to a common place.
This commit is contained in:
Benjamin Valentin 2019-12-11 15:43:20 +01:00
parent e4a33ca413
commit 22c2dbbbe5
2 changed files with 6 additions and 26 deletions
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1
drivers/Makefile.dep
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@ -529,6 +529,7 @@ endif
ifneq (,$(filter sht3x,$(USEMODULE)))
USEMODULE += xtimer
USEMODULE += checksum
FEATURES_REQUIRED += periph_i2c
endif

31
drivers/sht3x/sht3x.c
View File

@ -20,6 +20,7 @@
#include <errno.h>
#include <string.h>
#include "checksum/crc8.h"
#include "sht3x.h"
#include "xtimer.h"
@ -99,8 +100,10 @@ static int _status (sht3x_dev_t* dev, uint16_t* status);
static int _send_command(sht3x_dev_t* dev, uint16_t cmd);
static int _read_data(sht3x_dev_t* dev, uint8_t *data, uint8_t len);
/* helper functions */
static uint8_t _crc8 (uint8_t data[], int len);
static inline uint8_t _crc8(const void* buf, size_t len)
{
return crc8(buf, len, 0x31, 0xff);
}
/* ------------------------------------------------ */
@ -416,27 +419,3 @@ static int _status (sht3x_dev_t* dev, uint16_t* status)
DEBUG_DEV("status=%02x", dev, *status);
return SHT3X_OK;
}
static const uint8_t g_polynom = 0x31;
static uint8_t _crc8 (uint8_t data[], int len)
{
/* initialization value */
uint8_t crc = 0xff;
/* iterate over all bytes */
for (int i=0; i < len; i++)
{
crc ^= data[i];
for (int i = 0; i < 8; i++)
{
bool xor = crc & 0x80;
crc = crc << 1;
crc = xor ? crc ^ g_polynom : crc;
}
}
return crc;
}