#!/usr/bin/env python3
# -*- coding: UTF-8 -*-
"""
I2C EEPROM driver for AT24Cxx
EEPROM data sheet: https://ww1.microchip.com/downloads/en/DeviceDoc/doc0336.pdf
MIT License
Copyright (c) 2018 Mike Causer
Extended 2023 by brainelectronics
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"""
# system packages
from machine import I2C
from time import sleep_ms
class _Subscriptable():
def __getitem__(self, item):
return None
_subscriptable = _Subscriptable()
List = _subscriptable
Optional = _subscriptable
Union = _subscriptable
[docs]class EEPROM(object):
"""Driver for AT24Cxx I2C EEPROM"""
def __init__(self,
addr: int = 0x50,
pages: int = 128,
bpp: int = 32,
i2c: Optional[I2C] = None,
at24x: int = 0) -> None:
"""
Constructs a new instance
:param addr: The I2C bus address of the EEPROM
:type addr: int
:param pages: The number of pages of the EEPROM
:type pages: int
:param bpp: The bytes per page
:type bpp: int
:param i2c: I2C object
:type i2c: I2C
:param at24x: The specific AT24Cxx, either 32, 64, 128, 256, 512
:type at24x: int
"""
self._addr = addr
standard_eeproms = {
32: [128, 32], # 4KiB 32Kbits, 128 pages, 32 bytes/page
64: [256, 32], # 8KiB 64Kbits, 256 pages, 32 bytes/page
128: [256, 64], # 16KiB 128Kbits, 256 pages, 64 bytes/page
256: [512, 64], # 32KiB 256Kbits, 512 pages, 64 bytes/page
512: [512, 128], # 64KiB 512Kbits, 512 pages, 128 bytes/page
}
if at24x in standard_eeproms:
self._pages, self._bpp = standard_eeproms[at24x]
else:
self._pages = pages
self._bpp = bpp
if i2c is None:
# default assignment, check the docs
self._i2c = I2C(0)
else:
self._i2c = i2c
@property
def addr(self) -> int:
"""
Get the EEPROM I2C bus address
:returns: EEPROM I2C bus address
:rtype: int
"""
return self._addr
@property
def capacity(self) -> int:
"""
Get the storage capacity of the EEPROM
:returns: EEPROM capacity of the EEPROM in bytes
:rtype: int
"""
return self._pages * self._bpp
@property
def pages(self) -> int:
"""
Get the number of EEPROM pages
:returns: Number of pages of the EEPROM
:rtype: int
"""
return self._pages
@property
def bpp(self) -> int:
"""
Get the bytes per page of the EEPROM
:returns: Bytes per pages of the EEPROM
:rtype: int
"""
return self._bpp
[docs] def length(self) -> int:
"""
Get the EEPROM length
:returns: Number of cells in the EEPROM
:rtype: int
"""
return self.capacity
[docs] def read(self, addr: int, nbytes: int = 1) -> bytes:
"""
Read bytes from the EEPROM
:param addr: The start address
:type addr: int
:param nbytes: The number of bytes to read
:type nbytes: int
:returns: Data of EEPROM
:rtype: bytes
"""
if addr > self.capacity or addr < 0:
raise ValueError(
"Read address {} outside of device address range {}".
format(addr, self.capacity)
)
if addr + nbytes > self.capacity:
raise ValueError(
"Last read address {} outside of device address range {}".
format(addr + nbytes, self.capacity)
)
return self._i2c.readfrom_mem(self._addr, addr, nbytes, addrsize=16)
[docs] def write(self, addr: int, buf: Union[bytes, List[int], str]) -> None:
"""
Write data to the EEPROM
:param addr: The start address
:type addr: int
:param buf: The buffer to write to the EEPROM
:type buf: Union[bytes, List[int], str]
"""
offset = addr % self._bpp
partial = 0
if addr > self.capacity or addr < 0:
raise ValueError(
"Write address {} outside of device address range {}".
format(addr, self.capacity)
)
if addr + len(buf) > self.capacity:
raise ValueError(
"Last data at {} does not fit into device address range {}".
format(addr + len(buf), self.capacity)
)
# partial page write
if offset > 0:
partial = self._bpp - offset
self._i2c.writeto_mem(
self._addr, addr, buf[0:partial], addrsize=16
)
sleep_ms(5)
addr += partial
# full page write
for i in range(partial, len(buf), self._bpp):
self._i2c.writeto_mem(
self._addr,
addr + i - partial,
buf[i:i + self._bpp],
addrsize=16
)
sleep_ms(5)
[docs] def update(self, addr: int, buf: Union[bytes, List[int], str]) -> None:
"""
Update data in EEPROM
:param addr: The start address
:type addr: int
:param buf: The buffer to write to the EEPROM
:type buf: Union[bytes, List[int], str]
"""
for idx, ele in enumerate(buf):
this_addr = addr + idx
if isinstance(ele, int):
this_val = ele.to_bytes(1, 'big')
else:
this_val = str(ele).encode()
current_value = self.read(addr=this_addr) # returns bytes
if current_value != this_val:
self.write(addr=this_addr, buf=this_val)
# print("{}: {} -> {}".
# format(this_addr, current_value, this_val))
# else:
# print("No need to update value at {}".format(this_addr))
[docs] def wipe(self) -> None:
"""Wipe the complete EEPROM"""
page_buff = b'\xff' * self.bpp
for i in range(self.pages):
self.write(i * self.bpp, page_buff)
[docs] def print_pages(self, addr: int, nbytes: int) -> None:
"""
Print pages content with boundaries.
:param addr: The start address
:type addr: int
:param nbytes: The number of bytes to read
:type nbytes: int
"""
unknown_data_first_page = addr % self.bpp
unknown_data_last_page = self.bpp - (addr + nbytes) % self.bpp
if unknown_data_last_page % self.bpp == 0:
unknown_data_last_page = 0
data = self.read(addr=addr, nbytes=nbytes)
extended_data = (
b'?' * unknown_data_first_page +
data +
b'?' * unknown_data_last_page
)
sliced_data = [
extended_data[i: i + self.bpp] for i in range(0,
len(extended_data),
self.bpp)
]
print('Page {:->4}: 0 {} {}'.
format('x', '-' * (self.bpp - len(str(self.bpp))), self.bpp))
for idx, a_slice in enumerate(sliced_data):
print('Page {:->4}: {}'.format(idx, a_slice))