mirror of https://github.com/eldruin/ds323x-rs
160 lines
7.4 KiB
Markdown
160 lines
7.4 KiB
Markdown
# Rust DS3231, DS3232 and DS3234 Extremely Accurate Real-Time Clock Driver
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[](https://crates.io/crates/ds323x)
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[](https://docs.rs/ds323x)
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[](https://github.com/eldruin/ds323x-rs/actions?query=workflow%3ABuild)
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[](https://coveralls.io/r/eldruin/ds323x-rs?branch=master)
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This is a platform agnostic Rust driver for the DS3231, DS3232 and DS3234
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extremely accurate real-time clocks, based on the [`embedded-hal`] traits.
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[`embedded-hal`]: https://github.com/rust-embedded/embedded-hal
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This driver allows you to:
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- Read and set date and time in 12-hour and 24-hour format. See: `datetime`.
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- Read and set date and time individual elements. For example, see: `year`.
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- Enable and disable the real-time clock. See: `enable`.
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- Read the busy status. See `busy`.
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- Read whether the oscillator is or has been stopped. See `has_been_stopped`.
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- Clear the has-been-stopped flag. See `clear_has_been_stopped_flag`.
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- Set and read the aging offset. See `set_aging_offset`.
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- Select the function of the INT/SQW output pin. See `use_int_sqw_output_as_interrupt`.
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- Alarms:
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- Set alarms 1 and 2 with several matching policies. See `set_alarm1_day`.
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- Set alarms 1 and 2 for a time. See `set_alarm1_hms`.
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- Read whether alarms 1 or 2 have matched. See `has_alarm1_matched`.
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- Clear flag indicating that alarms 1 or 2 have matched. See `clear_alarm1_matched_flag`.
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- Enable and disable alarms 1 and 2 interrupt generation. See `enable_alarm1_interrupts`.
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- Wave generation:
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- Enable and disable the square-wave generation. See `enable_square_wave`.
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- Select the square-wave frequency. See `set_square_wave_frequency`.
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- Enable and disable the 32kHz output. See `enable_32khz_output`.
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- Enable and disable the 32kHz output when battery powered. See `enable_32khz_output_on_battery`.
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- Temperature conversion:
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- Read the temperature. See `temperature`.
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- Force a temperature conversion and time compensation. See `convert_temperature`.
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- Set the temperature conversion rate. See `set_temperature_conversion_rate`.
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- Enable and disable the temperature conversions when battery-powered. See `enable_temperature_conversions_on_battery`.
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## The devices
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This driver is compatible with the DS3231 and DS3232 I2C devices and the
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DS3234 SPI device.
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These devices are low-cost temperature-compensated crystal oscillator (TCXO)
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with a very accurate, temperature-compensated, integrated real-time clock
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(RTC) including 236/256 bytes of battery-backed SRAM, depending on the model.
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### DS3231 and DS3232 details
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The devices incorporate a battery input, and maintain accurate timekeeping
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when main power to the devices is interrupted. The integration of the
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crystal resonator enhances the long-term accuracy of the devices as well as
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reduces the piece-part count in a manufacturing line.
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The devices are available in commercial and industrial temperature ranges,
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and are offered in a 16-pin, 300-mil SO package.
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The RTC maintains seconds, minutes, hours, day, date, month, and year
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information. The date at the end of the month is automatically adjusted for
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months with fewer than 31 days, including corrections for leap year. The
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clock operates in either the 24-hour or 12-hour format with an AM/PM
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indicator. Two programmable time-of-day alarms and a programmable
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square-wave output are provided. Address and data are transferred serially
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through an I2C bidirectional bus.
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A precision temperature-compensated voltage reference and comparator
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circuit monitors the status of VCC to detect power failures, to provide a
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reset output, and to automatically switch to the backup supply when
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necessary. Additionally, the RST pin is monitored as a pushbutton
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input for generating a μP reset.
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### DS3234 details
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The DS3234 incorporates a precision, temperature-compensated voltage
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reference and comparator circuit to monitor VCC. When VCC drops below the
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power-fail voltage (VPF), the device asserts the RST output and also
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disables read and write access to the part when VCC drops below both VPF
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and VBAT. The RST pin is monitored as a pushbutton input for generating a
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μP reset. The device switches to the backup supply input and maintains
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accurate timekeeping when main power to the device is interrupted.
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The integration of the crystal resonator enhances the long-term accuracy of
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the device as well as reduces the piece-part count in a manufacturing line.
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The DS3234 is available in commercial and industrial temperature ranges,
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and is offered in an industry-standard 300-mil, 20-pin SO package.
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The DS3234 also integrates 256 bytes of battery-backed SRAM. In the event
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of main power loss, the contents of the memory are maintained by the power
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source connected to the V BAT pin. The RTC maintains seconds, minutes,
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hours, day, date, month, and year information. The date at the end of the
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month is automatically adjusted for months with fewer than 31 days,
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including corrections for leap year. The clock operates in either the
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24-hour or 12-hour format with AM/PM indicator. Two programmable
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time-of-day alarms and a programmable square-wave output are provided.
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Address and data are transferred serially by an SPI bidirectional bus.
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Datasheets:
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- [DS3231](https://datasheets.maximintegrated.com/en/ds/DS3231.pdf)
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- [DS3232](https://datasheets.maximintegrated.com/en/ds/DS3232.pdf)
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- [DS3234](https://datasheets.maximintegrated.com/en/ds/DS3234.pdf)
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## Usage
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To use this driver, import this crate and an `embedded_hal` implementation,
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then instantiate the appropriate device.
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In the following example an instance of the device DS3231 will be created.
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Other devices can be created with similar methods like:
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`Ds323x::new_ds3234(...)`.
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Please find additional examples using hardware in this repository: [driver-examples]
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[driver-examples]: https://github.com/eldruin/driver-examples
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```rust
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use ds323x::{DateTimeAccess, Ds323x, NaiveDate, Rtcc};
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use linux_embedded_hal::I2cdev;
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fn main() {
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let dev = I2cdev::new("/dev/i2c-1").unwrap();
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let mut rtc = Ds323x::new_ds3231(dev);
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let datetime = NaiveDate::from_ymd_opt(2020, 5, 1)
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.unwrap()
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.and_hms_opt(19, 59, 58)
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.unwrap();
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rtc.set_datetime(&datetime).unwrap();
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// do something else...
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let time = rtc.time().unwrap();
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println!("Time: {}", time);
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let _dev = rtc.destroy_ds3231();
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}
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```
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## Support
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For questions, issues, feature requests like compatibility with other devices and other
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changes, please file an
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[issue in the github project](https://github.com/eldruin/ds323x-rs/issues).
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## Minimum Supported Rust Version (MSRV)
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This crate is guaranteed to compile on stable Rust 1.35 and up. It *might*
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compile with older versions but that may change in any new patch release.
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## License
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Licensed under either of
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* Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
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http://www.apache.org/licenses/LICENSE-2.0)
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* MIT license ([LICENSE-MIT](LICENSE-MIT) or
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http://opensource.org/licenses/MIT)
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at your option.
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### Contributing
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Unless you explicitly state otherwise, any contribution intentionally submitted
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for inclusion in the work by you, as defined in the Apache-2.0 license, shall
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be dual licensed as above, without any additional terms or conditions.
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