When DS18 returns 0xFE6F (corresponding to -25.0625 °C), `ds18_read` returns 13877 whereas it should return -2506. This commit fixes this issue.
When DS18 returns 0xFE6F (corresponding to -25.0625 °C), `ds18_read` returns 13877 whereas it should return -2506. This commit fixes this issue.