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//! This is a platform agnostic Rust driver for the 24x series serial EEPROM,
//! based on the [`embedded-hal`] traits.
//!
//! [`embedded-hal`]: https://github.com/rust-embedded/embedded-hal
//!
//! This driver allows you to:
//! - Read a single byte from a memory address. See [`read_byte()`].
//! - Read a byte array starting on a memory address. See: [`read_data()`].
//! - Read the current memory address (please read notes). See: [`read_current_address()`].
//! - Write a byte to a memory address. See: [`write_byte()`].
//! - Write a byte array (up to a memory page) to a memory address. See: [`write_page()`].
//!
//! [`read_byte()`]: struct.Eeprom24x.html#method.read_byte
//! [`read_data()`]: struct.Eeprom24x.html#method.read_data
//! [`read_current_address()`]: struct.Eeprom24x.html#method.read_current_address
//! [`write_byte()`]: struct.Eeprom24x.html#method.write_byte
//! [`write_page()`]: struct.Eeprom24x.html#method.write_page
//!
//! Can be used at least with the devices listed below.
//!
//! ## The devices
//!
//! These devices provides a number of bits of serial electrically erasable and
//! programmable read only memory (EEPROM) organized as a number of words of 8 bits
//! each. The devices' cascadable feature allows up to 8 devices to share a common
//! 2-wire bus. The devices are optimized for use in many industrial and commercial
//! applications where low power and low voltage operation are essential.
//!
//! | Device | Memory bits | 8-bit words | Page size | Datasheet |
//! |-------:|------------:|------------:|----------:|:-----------|
//! | 24x00 | 128 bits | 16 | N/A | [24C00] |
//! | 24x01 | 1 Kbit | 128 | 8 bytes | [AT24C01] |
//! | 24x02 | 2 Kbit | 256 | 8 bytes | [AT24C02] |
//! | 24x04 | 4 Kbit | 512 | 16 bytes | [AT24C04] |
//! | 24x08 | 8 Kbit | 1,024 | 16 bytes | [AT24C08] |
//! | 24x16 | 16 Kbit | 2,048 | 16 bytes | [AT24C16] |
//! | 24x32 | 32 Kbit | 4,096 | 32 bytes | [AT24C32] |
//! | 24x64 | 64 Kbit | 8,192 | 32 bytes | [AT24C64] |
//! | 24x128 | 128 Kbit | 16,384 | 64 bytes | [AT24C128] |
//! | 24x256 | 256 Kbit | 32,768 | 64 bytes | [AT24C256] |
//! | 24x512 | 512 Kbit | 65,536 | 128 bytes | [AT24C512] |
//! | 24xM01 | 1 Mbit | 131,072 | 256 bytes | [AT24CM01] |
//! | 24xM02 | 2 Mbit | 262,144 | 256 bytes | [AT24CM02] |
//!
//! [24C00]: http://ww1.microchip.com/downloads/en/DeviceDoc/24AA00-24LC00-24C00-Data-Sheet-20001178J.pdf
//! [AT24C01]: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8871F-SEEPROM-AT24C01D-02D-Datasheet.pdf
//! [AT24C02]: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8871F-SEEPROM-AT24C01D-02D-Datasheet.pdf
//! [AT24C04]: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8896E-SEEPROM-AT24C04D-Datasheet.pdf
//! [AT24C08]: http://ww1.microchip.com/downloads/en/DeviceDoc/AT24C08D-I2C-Compatible-2-Wire-Serial-EEPROM-20006022A.pdf
//! [AT24C16]: http://ww1.microchip.com/downloads/en/DeviceDoc/20005858A.pdf
//! [AT24C32]: http://ww1.microchip.com/downloads/en/devicedoc/doc0336.pdf
//! [AT24C64]: http://ww1.microchip.com/downloads/en/devicedoc/doc0336.pdf
//! [AT24C128]: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8734-SEEPROM-AT24C128C-Datasheet.pdf
//! [AT24C256]: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8568-SEEPROM-AT24C256C-Datasheet.pdf
//! [AT24C512]: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8720-SEEPROM-AT24C512C-Datasheet.pdf
//! [AT24CM01]: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8812-SEEPROM-AT24CM01-Datasheet.pdf
//! [AT24CM02]: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8828-SEEPROM-AT24CM02-Datasheet.pdf
//!
//! ## Usage examples (see also examples folder)
//!
//! To create a new instance you can use the `new_<device>` methods.
//! There are many compatible vendors so the method has a somewhat generic name.
//! For example, if you are using an AT24C32, you can create a device by calling
//! `Eeprom24x::new_24x32(...)`.
//! Please refer to the [device table](#the-devices) above for more examples.
//!
//! ### Instantiating with the default address
//!
//! Import this crate and an `embedded_hal` implementation, then instantiate
//! the device:
//!
//! ```no_run
//! extern crate linux_embedded_hal as hal;
//! extern crate eeprom24x;
//!
//! use hal::I2cdev;
//! use eeprom24x::{ Eeprom24x, SlaveAddr };
//!
//! # fn main() {
//! let dev = I2cdev::new("/dev/i2c-1").unwrap();
//! let address = SlaveAddr::default();
//! // using the AT24C256
//! let mut eeprom = Eeprom24x::new_24x256(dev, address);
//! # }
//! ```
//!
//! ### Providing an alternative address
//!
//! ```no_run
//! extern crate linux_embedded_hal as hal;
//! extern crate eeprom24x;
//!
//! use hal::I2cdev;
//! use eeprom24x::{ Eeprom24x, SlaveAddr };
//!
//! # fn main() {
//! let dev = I2cdev::new("/dev/i2c-1").unwrap();
//! let (a2, a1, a0) = (false, false, true);
//! let address = SlaveAddr::Alternative(a2, a1, a0);
//! let mut eeprom = Eeprom24x::new_24x256(dev, address);
//! # }
//! ```
//!
//! ### Writting and reading a byte
//!
//! ```no_run
//! extern crate linux_embedded_hal as hal;
//! extern crate eeprom24x;
//!
//! use hal::I2cdev;
//! use eeprom24x::{ Eeprom24x, SlaveAddr };
//!
//! # fn main() {
//! let dev = I2cdev::new("/dev/i2c-1").unwrap();
//! let mut eeprom = Eeprom24x::new_24x256(dev, SlaveAddr::default());
//! let address = [0x12, 0x34];
//! let data = 0xAB;
//! eeprom.write_byte(address, data);
//! // EEPROM enters internally-timed write cycle. Will not respond for some time.
//! let retrieved_data = eeprom.read_byte(address);
//! # }
//! ```
//!
//! ### Writting a page
//!
//! ```no_run
//! extern crate linux_embedded_hal as hal;
//! extern crate eeprom24x;
//!
//! use hal::I2cdev;
//! use eeprom24x::{ Eeprom24x, SlaveAddr };
//!
//! # fn main() {
//! let dev = I2cdev::new("/dev/i2c-1").unwrap();
//! let mut eeprom = Eeprom24x::new_24x256(dev, SlaveAddr::default());
//! let address = [0x12, 0x34];
//! let data = [0xAB; 64];
//! eeprom.write_page(address, &data);
//! // EEPROM enters internally-timed write cycle. Will not respond for some time.
//! # }
//! ```
#![deny(missing_docs, unsafe_code, warnings)]
#![no_std]
extern crate embedded_hal as hal;
use core::marker::PhantomData;
use hal::blocking::i2c::{Write, WriteRead};
/// All possible errors in this crate
#[derive(Debug)]
pub enum Error<E> {
/// I²C bus error
I2C(E),
/// Too much data passed for a write
TooMuchData,
}
/// Possible slave addresses
#[derive(Debug, Clone, Copy)]
pub enum SlaveAddr {
/// Default slave address
Default,
/// Alternative slave address providing bit values for A2, A1 and A0
Alternative(bool, bool, bool),
}
impl Default for SlaveAddr {
/// Default slave address
fn default() -> Self {
SlaveAddr::Default
}
}
impl SlaveAddr {
/// Get slave address as u8
fn addr(self) -> u8 {
match self {
SlaveAddr::Default => 0b101_0000,
SlaveAddr::Alternative(a2, a1, a0) =>
SlaveAddr::default().addr() |
((a2 as u8) << 2) |
((a1 as u8) << 1) |
a0 as u8
}
}
}
/// Page size markers
pub mod page_size {
/// No page write supported. e.g. for AT24x00
pub struct No(());
/// 8-byte pages. e.g. for AT24x01, AT24x02
pub struct B8(());
/// 16-byte pages. e.g. for AT24x04, AT24x08, AT24x16
pub struct B16(());
/// 32-byte pages. e.g. for AT24x32, AT24x64
pub struct B32(());
/// 64-byte pages. e.g. for AT24x128, AT24x256
pub struct B64(());
/// 128-byte pages. e.g. for AT24x512
pub struct B128(());
/// 256-byte pages. e.g. for AT24xM01, AT24xM02
pub struct B256(());
}
/// EEPROM24X driver
#[derive(Debug, Default)]
pub struct Eeprom24x<I2C, PS> {
/// The concrete I²C device implementation.
i2c: I2C,
/// The I²C device address.
address: SlaveAddr,
/// Page size marker type.
_ps: PhantomData<PS>,
}
/// Common methods
impl<I2C, E, PS> Eeprom24x<I2C, PS>
where
I2C: Write<Error = E> + WriteRead<Error = E>,
{
/// Destroy driver instance, return I²C bus instance.
pub fn destroy(self) -> I2C {
self.i2c
}
/// Write a single byte in an address.
///
/// After writing a byte, the EEPROM enters an internally-timed write cycle
/// to the nonvolatile memory.
/// During this time all inputs are disabled and the EEPROM will not
/// respond until the write is complete.
pub fn write_byte(&mut self, address: [u8; 2], data: u8) -> Result<(), Error<E>> {
let payload = [address[0], address[1], data];
self.i2c
.write(self.address.addr(), &payload)
.map_err(Error::I2C)
}
/// Read a single byte from an address.
pub fn read_byte(&mut self, address: [u8; 2]) -> Result<u8, Error<E>> {
let mut data = [0; 1];
self.i2c
.write_read(self.address.addr(), &[address[0], address[1]], &mut data)
.map_err(Error::I2C)
.and(Ok(data[0]))
}
/// Read starting in an address as many bytes as necessary to fill the data array provided.
pub fn read_data(&mut self, address: [u8; 2], data: &mut [u8]) -> Result<(), Error<E>> {
self.i2c
.write_read(self.address.addr(), &[address[0], address[1]], data)
.map_err(Error::I2C)
}
}
/// Specialization for platforms which implement `embedded_hal::blocking::i2c::Read`
impl<I2C, E, PS> Eeprom24x<I2C, PS>
where
I2C: hal::blocking::i2c::Read<Error = E>,
{
/// Read the contents of the last address accessed during the last read
/// or write operation, _incremented by one_.
///
/// Note: This may not be available on your platform.
pub fn read_current_address(&mut self) -> Result<u8, Error<E>> {
let mut data = [0];
self.i2c
.read(self.address.addr(), &mut data)
.map_err(Error::I2C)
.and(Ok(data[0]))
}
}
/// Specialization for devices without page access (e.g. 24C00)
impl<I2C, E> Eeprom24x<I2C, page_size::No>
where
I2C: Write<Error = E> + WriteRead<Error = E>,
{
/// Create a new instance of a 24x00 device (e.g. 24C00)
pub fn new_24x00(i2c: I2C, address: SlaveAddr) -> Self {
Eeprom24x {
i2c,
address,
_ps: PhantomData,
}
}
}
macro_rules! impl_create {
( $dev:expr, $part:expr, $create:ident ) => {
impl_create!{
@gen [$create, concat!("Create a new instance of a ", $dev, " device (e.g. ", $part, ")")]
}
};
(@gen [$create:ident, $doc:expr] ) => {
#[doc = $doc]
pub fn $create(i2c: I2C, address: SlaveAddr) -> Self {
Self::new(i2c, address)
}
};
}
macro_rules! impl_for_page_size {
( $PS:ident, $page_size:expr, $( [ $dev:expr, $part:expr, $create:ident ] ),* ) => {
impl_for_page_size!{
@gen [$PS, $page_size,
concat!("Specialization for devices with a page size of ", stringify!($page_size), " bytes."),
concat!("Create generic instance for devices with a page size of ", stringify!($page_size), " bytes."),
$( [ $dev, $part, $create ] ),* ]
}
};
(@gen [$PS:ident, $page_size:expr, $doc_impl:expr, $doc_new:expr, $( [ $dev:expr, $part:expr, $create:ident ] ),* ] ) => {
#[doc = $doc_impl]
impl<I2C, E> Eeprom24x<I2C, page_size::$PS>
where
I2C: Write<Error = E>
{
$(
impl_create!($dev, $part, $create);
)*
#[doc = $doc_new]
fn new(i2c: I2C, address: SlaveAddr) -> Self {
Eeprom24x {
i2c,
address,
_ps: PhantomData,
}
}
/// Write up to a page starting in an address.
///
/// The maximum amount of data that can be written depends on the page
/// size of the device. If too much data is passed, the error
/// `Error::TooMuchData` will be returned.
///
/// After writing a byte, the EEPROM enters an internally-timed write cycle
/// to the nonvolatile memory.
/// During this time all inputs are disabled and the EEPROM will not
/// respond until the write is complete.
pub fn write_page(&mut self, address: [u8; 2], data: &[u8]) -> Result<(), Error<E>> {
if data.len() == 0 {
return Ok(());
}
if data.len() > $page_size {
// This would actually be supported by the EEPROM but
// the data would be overwritten
return Err(Error::TooMuchData);
}
let mut payload: [u8; 2 + $page_size] = [0; 2 + $page_size];
payload[0] = address[0];
payload[1] = address[1];
payload[2..=(1 + data.len())].copy_from_slice(&data);
self.i2c
.write(self.address.addr(), &payload[..=(1 + data.len())])
.map_err(Error::I2C)
}
}
};
}
impl_for_page_size!(
B8,
8,
["24x01", "AT24C01", new_24x01],
["24x02", "AT24C02", new_24x02]
);
impl_for_page_size!(
B16,
16,
["24x04", "AT24C04", new_24x04],
["24x08", "AT24C08", new_24x08],
["24x16", "AT24C16", new_24x16]
);
impl_for_page_size!(
B32,
32,
["24x32", "AT24C32", new_24x32],
["24x64", "AT24C64", new_24x64]
);
impl_for_page_size!(
B64,
64,
["24x128", "AT24C128", new_24x128],
["24x256", "AT24C256", new_24x256]
);
impl_for_page_size!(B128, 128, ["24x512", "AT24C512", new_24x512]);
impl_for_page_size!(
B256,
256,
["24xM01", "AT24CM01", new_24xm01],
["24xM02", "AT24CM02", new_24xm02]
);
#[cfg(test)]
mod tests {
extern crate embedded_hal_mock as hal;
use super::*;
#[test]
fn default_address_is_correct() {
assert_eq!(0b101_0000, SlaveAddr::default().addr());
}
#[test]
fn can_generate_alternative_addresses() {
assert_eq!(0b101_0000, SlaveAddr::Alternative(false, false, false).addr());
assert_eq!(0b101_0001, SlaveAddr::Alternative(false, false, true).addr());
assert_eq!(0b101_0010, SlaveAddr::Alternative(false, true, false).addr());
assert_eq!(0b101_0100, SlaveAddr::Alternative( true, false, false).addr());
assert_eq!(0b101_0111, SlaveAddr::Alternative( true, true, true).addr());
}
}