Add low voltage warnings

CHANGELOG.md

@@ -0,0 +1,12 @@
+# Changelog
+
+All notable changes to this project will be documented in this file, in reverse chronological order by release.
+
+## [0.5.0](https://github.com/tuupola/bm8563/compare/0.4.0...master) - unreleased
+
+### Added
+- Support for low voltage warnings ([#3](https://github.com/tuupola/bm8563/pull/3)).
+
+## 0.4.0 - 2020-20-05
+
+Initial release.

bm8563.c

@@ -73,8 +73,6 @@ bm8563_err_t bm8563_read(const bm8563_t *bm, struct tm *time)
         return status;
     }
 
-    /* TODO: low voltage warning */
-
     /* 0..59 */
     bcd = buffer[0] & 0b01111111;
     time->tm_sec = bcd2decimal(bcd);
@@ -111,6 +109,11 @@ bm8563_err_t bm8563_read(const bm8563_t *bm, struct tm *time)
     /* Calculate tm_yday. */
     mktime(time);
 
+    /* low voltage warning */
+    if (buffer[0] & 0b10000000) {
+        return BM8563_ERR_LOW_VOLTAGE;
+    }
+
     return BM8563_OK;
 }
 

bm8563.h

@@ -54,7 +54,8 @@ extern "C" {
 #define	BM8563_TIME_SIZE        (0x07)
 #define	BM8563_CENTURY_BIT      (0b10000000)
 
-#define BM8563_OK         (0x00)
+#define BM8563_OK               (0x00)
+#define BM8563_ERR_LOW_VOLTAGE  (0x80)
 
 /* These should be provided by the HAL. */
 typedef struct {

tests/mock_i2c.c

@@ -49,6 +49,12 @@ int32_t mock_i2c_write(void *handle, uint8_t address, uint8_t reg, const uint8_t
     return BM8563_OK;
 }
 
+int32_t mock_i2c_low_voltage_read(void *handle, uint8_t address, uint8_t reg, uint8_t *buffer, uint16_t size) {
+    memcpy(buffer, memory, size);
+    buffer[0] |= 0b10000000;
+    return BM8563_OK;
+}
+
 int32_t mock_failing_i2c_read(void *handle, uint8_t address, uint8_t reg, uint8_t *buffer, uint16_t size) {
     return 3;
 }

tests/mock_i2c.h

@@ -36,5 +36,7 @@ SPDX-License-Identifier: MIT
 int32_t mock_i2c_read(void *handle, uint8_t address, uint8_t reg, uint8_t *buffer, uint16_t size);
 int32_t mock_i2c_write(void *handle, uint8_t address, uint8_t reg, const uint8_t *buffer, uint16_t size);
 
+int32_t mock_i2c_low_voltage_read(void *handle, uint8_t address, uint8_t reg, uint8_t *buffer, uint16_t size);
+
 int32_t mock_failing_i2c_read(void *handle, uint8_t address, uint8_t reg, uint8_t *buffer, uint16_t size);
 int32_t mock_failing_i2c_write(void *handle, uint8_t address, uint8_t reg, const uint8_t *buffer, uint16_t size);

tests/unit.c

@@ -69,9 +69,20 @@ TEST should_fail_read_time(void) {
     PASS();
 }
 
+TEST should_get_low_voltage_warning(void) {
+    struct tm datetime = {0};
+    bm8563_t bm;
+    bm.read = &mock_i2c_low_voltage_read;
+    bm.write = &mock_i2c_write;
+
+    ASSERT(BM8563_OK == bm8563_init(&bm));
+    ASSERT(BM8563_ERR_LOW_VOLTAGE == bm8563_read(&bm, &datetime));
+    PASS();
+}
+
 TEST should_read_and_write_time(void) {
-    struct tm datetime = {0};;
-    struct tm datetime2 = {0};;
+    struct tm datetime = {0};
+    struct tm datetime2 = {0};
     char buffer[128];
     bm8563_t bm;
     bm.read = &mock_i2c_read;
@@ -129,6 +140,7 @@ int main(int argc, char **argv) {
     RUN_TEST(should_fail_init);
     RUN_TEST(should_init);
     RUN_TEST(should_fail_read_time);
+    RUN_TEST(should_get_low_voltage_warning);
     RUN_TEST(should_read_and_write_time);
     RUN_TEST(should_handle_century);