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sleemanj / DS3231_Simple

An Arduino Library for EASY communication with DS3231 I2C RTC Clock and Atmel AT24C32 I2C EEPROM commonly found on the same board. Implements setting, getting the time/date, setting, checking and clearing alarms, and dead-easy circular-buffered logging of data with timestamp.
MIT License
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Count number of logs #12

Closed geologic closed 6 years ago

geologic commented 6 years ago

Hi

I need to count the number of log entries before call readlog(), so i exposed findEEPROMReadAddress() and findEEPROMWriteAddress() (moved them from protected to public on the library). I use this code to get the number of logs:

uint16_t start=Clock.findEEPROMReadAddress(); uint16_t end=Clock.findEEPROMWriteAddress(); int size=end-start; //size of log in bytes When i print size, it gives me odd values. I tested writing 2 log entries of 12 bytes each (including timestamp) and the output is 2424 (should be 24). If i write 5 log entries the output is 6060 (should be 60). It seems that Clock.findEEPROMWriteAddress() reports some kind of shifting...

Im i doing something wrong?

sleemanj commented 6 years ago

The buffer is circular, the read address could be before or after the write address and additionally there may be gaps.

Read the comments here

https://github.com/sleemanj/DS3231_Simple/blob/master/DS3231_Simple.h#L355

to implement a count, study https://github.com/sleemanj/DS3231_Simple/blob/master/DS3231_Simple.cpp#L162 and see how it works, it reads all the log entries, so you can do the same thing and instead of looking for the oldest, keep a count.

On 2018-05-13 23:23, geologic wrote:

Hi

I need to count the number of log entries before call readlog(), so i exposed findEEPROMReadAddress() and findEEPROMWriteAddress() (moved them from protected to public on the library). I use this code to get the number of logs:

uint16_t start=Clock.findEEPROMReadAddress(); uint16_t end=Clock.findEEPROMWriteAddress(); int size=end-start; //size of log in bytes When i print size, it gives me odd values. I tested writing 2 log entries of 12 bytes each (including timestamp) and the output is 2424 (should be 24). If i write 5 log entries the output is 6060 (should be 60). It seems that Clock.findEEPROMWriteAddress() reports some kind of shifting...

Im i doing something wrong?

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[1] https://github.com/sleemanj/DS3231_Simple/issues/12 [2] https://github.com/notifications/unsubscribe-auth/AAMpaQ-1cNLFqqkS424Yq6Jg95cWlptOks5tyBewgaJpZM4T8wq2

geologic commented 6 years ago

Thanks. I cloned findEEPROMReadAddress() and changed like you suggested to return the number of logs.