added Exposure code, DS3231, SSD1306, interfaces, started with protocol buffers impl.

components/ds3231/include/ds3231.h

@@ -0,0 +1,78 @@
+// Copyright 2020 Lukas Haubaum
+//
+// Licensed under the GNU Affero General Public License, Version 3;
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     https://www.gnu.org/licenses/agpl-3.0.html
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#ifndef _ds3231_H_
+#define _ds3231_H_
+
+#include <time.h>
+
+// I2C address
+#define DS3231_ADDRESS 0x68
+
+// I2C registers
+#define DS3231_TIME 0x00
+#define DS3231_SECONDS 0x00
+#define DS3231_MINUTES 0x01
+#define DS3231_HOURS 0x02
+#define DS3231_DAY 0x03
+#define DS3231_DATE 0x04
+#define DS3231_MONTH 0x05
+#define DS3231_YEAR 0x06
+#define DS3231_ALARM1_SECONDS 0x07
+#define DS3231_ALARM1_MINUTES 0x08
+#define DS3231_ALARM1_HOURS 0x09
+#define DS3231_ALARM1_DATE 0x0A
+#define DS3231_ALARM2_MINUTES 0x0B
+#define DS3231_ALARM2_HOURS 0x0C
+#define DS3231_ALARM2_DATE 0x0D
+#define DS3231_CONTROL 0x0E
+#define DS3231_STATUS 0x0F
+#define DS3231_AGING_OFFSET 0x10
+#define DS3231_MSB_TEMP 0x11
+#define DS3231_LSB_TEMP 0x12
+
+// control registers
+#define DS3231_CONTROL_A1IE 0x01
+#define DS3231_CONTROL_A2IE 0x02
+#define DS3231_CONTROL_INTCN 0x04
+#define DS3231_CONTROL_RS1 0x08
+#define DS3231_CONTROL_RS2 0x10
+#define DS3231_CONTROL_CONV 0x20
+#define DS3231_CONTROL_BBSQW 0x40
+#define DS3231_CONTROL_EOSC 0x80
+
+// status registers
+#define DS3231_STATUSL_A1F 0x01
+#define DS3231_STATUSL_A2F 0x02
+#define DS3231_STATUSL_BSY 0x04
+#define DS3231_STATUSL_EN32KHZ 0x08
+#define DS3231_STATUSL_OSF 0x80
+
+// flags
+#define DS3231_CENTURY_FLAG 0x80
+#define DS3231_12_HOUR_FLAG 0x40
+#define DS3231_PM_HOUR_FLAG 0x20
+#define DS3231_12_HOUR_MASK 0x1F
+#define DS3231_MONTH_MASK 0x1F
+
+/**
+ * @brief Read time from DS3231
+ */
+void ds3231_get_time(struct tm *time);
+
+/**
+ * @brief Write time to DS3231
+ */
+void ds3231_set_time(struct tm *time);
+
+#endif