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https://github.com/mcauser/micropython-tinyrtc-i2c

MicroPython driver for TinyRTC I2C modules with DS1307 RTC and AT24C32N EEPROM
https://github.com/mcauser/micropython-tinyrtc-i2c

at24c32 ds1307 eeprom micropython rtc tinyrtc-i2c

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MicroPython driver for TinyRTC I2C modules with DS1307 RTC and AT24C32N EEPROM

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README 

        
# MicroPython TinyRTC I2C module



MicroPython driver for the TinyRTC I2C module, featuring a DS1307 RTC and AT24C32N EEPROM.



![demo](docs/demo.jpg)



## Pins



Pins are available on both sides. You can use either. One side exposes more pins.



Pin | Name            | Description

--- | --------------- | ----------------------------------------------------

BAT | Battery Voltage | For monitoring battery voltage

GND | Ground          | Ground

VCC | Input Supply    | +5V power for module and to charge coin cell battery

SDA | I2C Data        | I2C data for DS1307 and EEPROM

SCL | I2C Clock       | I2C clock for DS1307 and EEPROM

DS  | DS18B20         | Optional temperature sensor 1-wire data

SQ  | Square Wave     | Optional square wave or logic level output



# DS1307 RTC Examples



```python

# VCC-GND STM32F407VET6 on SPI3

>>> from machine import I2C, Pin

>>> i2c = I2C(3) # SCL=A8, SDA=C9

>>> i2c.scan()

[80, 104]



# 80 == 0x50 == AT24C32N EEPROM

# 104 == 0x68 == DS1307



>>> import ds1307

>>> ds = ds1307.DS1307(i2c)

ds.datetime()

ds.datetime(now)



# initial datetime value, oscillator disabled

>>> ds.datetime()

(2000, 1, 1, 0, 0, 0, 0, 0)



# read datetime after 1 second (no change)

>>> ds.datetime()

(2000, 1, 1, 0, 0, 0, 0, 0)



# enable oscillator

>>> ds.halt(False)



# read datetime after 1 second

>>> ds.datetime()

(2000, 1, 1, 0, 0, 0, 1, 0)



# read datetime after 1 more second

>>> ds.datetime()

(2000, 1, 1, 0, 0, 0, 2, 0)



# read datetime after 1 more second

>>> ds.datetime()

(2000, 1, 1, 0, 0, 0, 3, 0)



# set the datetime 24th March 2018 at 1:45:21 PM

>>> now = (2018, 3, 24, 6, 13, 45, 21, 0)

>>> ds.datetime(now)



# read datetime after 1 second

>>> ds.datetime()

(2018, 3, 24, 6, 13, 45, 22, 0)



# read datetime after 1 second

>>> ds.datetime()

(2018, 3, 24, 6, 13, 45, 23, 0)



# disable oscillator

>>> ds.halt(True)



# read datetime after 1 second

>>> ds.datetime()

(2018, 3, 24, 6, 13, 45, 24, 0)



# read datetime after 1 second (no change)

>>> ds.datetime()

(2018, 3, 24, 6, 13, 45, 24, 0)



# minute increment (00:00:59 -> 00:01:00)

>>> ds.datetime((2018, 3, 24, 6, 0, 0, 58, 0))

>>> ds.datetime()

(2018, 3, 24, 6, 0, 0, 59, 0)

>>> ds.datetime()

(2018, 3, 24, 6, 0, 1, 0, 0)



# hour increment (00:59:59 -> 01:00:00)

>>> ds.datetime((2018, 3, 24, 6, 0, 59, 58, 0))

>>> ds.datetime()

(2018, 3, 24, 6, 0, 59, 59, 0)

>>> ds.datetime()

(2018, 3, 24, 6, 1, 0, 0, 0)



# day + weekday increment (23:59:59 Sat -> 00:00:00 Sun)

>>> ds.datetime((2018, 3, 24, 6, 23, 59, 58, 0))

>>> ds.datetime()

(2018, 3, 24, 6, 23, 59, 59, 0)

>>> ds.datetime()

(2018, 3, 25, 0, 0, 0, 0, 0)



# month increment (Wed 28th Feb 2018 -> Thu 1st Mar 2018)

>>> ds.datetime((2018, 2, 28, 3, 23, 59, 58, 0))

>>> ds.datetime()

(2018, 2, 28, 3, 23, 59, 59, 0)

>>> ds.datetime()

(2018, 3, 1, 4, 0, 0, 0, 0)



# month increment on leap year Feb has 29 days (Sun 28th Feb 2016 -> Mon 29th Feb 2016)

>>> ds.datetime((2016, 2, 28, 0, 23, 59, 58, 0))

>>> ds.datetime()

(2016, 2, 28, 0, 23, 59, 59, 0)

>>> ds.datetime()

(2016, 2, 29, 1, 0, 0, 0, 0)



# month increment on leap year (Mon 29th Feb 2016 -> Tue 1st Mar 2016)

>>> ds.datetime((2016, 2, 29, 1, 23, 59, 58, 0))

>>> ds.datetime()

(2016, 2, 29, 1, 23, 59, 59, 0)

>>> ds.datetime()

(2016, 3, 1, 2, 0, 0, 0, 0)



# year increment (31st Dec 2018 -> 1st Jan 2019)

>>> ds.datetime((2018, 12, 31, 1, 23, 59, 58, 0))

>>> ds.datetime()

(2018, 12, 31, 1, 23, 59, 59, 0)

>>> ds.datetime()

(2019, 1, 1, 2, 0, 0, 0, 0)



# square wave output on pin SQ - 1Hz

>>> ds.square_wave(1, 0)



# square wave output on pin SQ - 4.096kHz

>>> ds.square_wave(4, 0)



# square wave output on pin SQ - 8.192kHz

>>> ds.square_wave(8, 0)



# square wave output on pin SQ - 32.768kHz

>>> ds.square_wave(32, 0)



# logic level output on pin SQ - high

>>> ds.square_wave(0, 1)



# logic level output on pin SQ - low

>>> ds.square_wave(0, 0)

```



# DS18B20 1-Wire Temperature Sensor Examples



```python

>>> from machine import Pin

>>> import onewire

>>> ow = onewire.OneWire(Pin('A9'))

>>> ow.scan()

[bytearray(b'(\xc9E\x01\x00\x00\x80/')]



>>> import time, ds18x20

>>> ds = ds18x20.DS18X20(ow)

>>> roms = ds.scan()

>>> ds.convert_temp()

>>> time.sleep_ms(750)

>>> for rom in roms:

...     print(ds.read_temp(rom))

23.8125

```



# AT24C32N EEPROM Examples



```python

>>> from machine import I2C, Pin

>>> i2c = I2C(3) # SCL=A8, SDA=C9

>>> i2c.scan()

[80, 104]



>>> import at24c32n

>>> eeprom = at24c32n.AT24C32N(i2c)



# read 32 bytes starting from memory address 0

>>> eeprom.read(0, 32)

b'\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff'



# write hello world to memory address 0

>>> eeprom.write(0, 'hello world')



# read back the hello world

>>> eeprom.read(0, 32)

b'hello world\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff'

>>> eeprom.read(0, 11)

b'hello world'



# write multiple pages (32 bytes per page)

>>> eeprom.write(0, b'abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ')



# read multiple pages (32 bytes per page)

>>> eeprom.read(0,64)

b'abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ\xff\xff'



# mutliple page writes (fill pages 0 and 1 with test data)

# write is performed in two steps, "0" x 32 in the first page, then "1" x 32 in the next page

# memory address was at the start of a page boundary so each write is a full 32 byte page write

>>> eeprom.write(0, b'0000000000000000000000000000000011111111111111111111111111111111')

>>> eeprom.read(0,64)

b'0000000000000000000000000000000011111111111111111111111111111111'



# partial page writes

# write some bytes spanning two pages, not starting at a page boundary

# write is performed in two steps, "abc" in the first page then "def" in the next page

>>> eeprom.write(29, b'abcdef')

>>> eeprom.read(0,64)

b'00000000000000000000000000000abcdef11111111111111111111111111111'



# fill entire eeprom with 0xFF

>>> buf = b'\xff' * 32

>>> for i in range(128):

...     eeprom.write(i*32, buf)



# show page boundaries

>>> for i in range(128):

...     eeprom.write(i*32, '|-Page-{:-<24}|'.format(i))

>>> eeprom.read(0,128)

b'|-Page-0-----------------------||-Page-1-----------------------||-Page-2-----------------------||-Page-3-----------------------|'



# read entire eeprom

>>> eeprom.read(0,4096)

```



## PyBoard / STM32F4 built-in RTC



You do not need this module if you are using a PyBoard or STM32 microcontroller with [built in RTC hardware](http://www.st.com/content/ccc/resource/technical/document/application_note/7a/9c/de/da/84/e7/47/8a/DM00025071.pdf/files/DM00025071.pdf/jcr:content/translations/en.DM00025071.pdf).



Simply add a coin cell battery between GND + VBAT and use [pyb.RTC](http://docs.micropython.org/en/latest/pyboard/library/pyb.RTC.html#pyb-rtc).



On the early pyboards, VBAT is the backup battery for the RTC. On the newer boards, VBAT is for powering the pyboard using a battery and the RTC battery is called Vbackup.

- Dave Hylands on the [micropython forum](https://forum.micropython.org/viewtopic.php?f=6&t=229&p=15352&hilit=vbat#p15352)



```python

# on the PyBoard or a STM32F407

rtc = pyb.RTC()

# set time

rtc.datetime((2018, 3, 24, 6, 13, 45, 21, 0))

# attach battery between GND + VBAT

# disconnect, reconnect

# get time

print(rtc.datetime())

```



## Troubleshooting



If you are using the ESP32 [loboris port](https://github.com/loboris/MicroPython_ESP32_psRAM_LoBo), swap the `addrsize=16` for a `adrlen=2`.



## Parts



* [TinyRTC I2C module](https://www.aliexpress.com/item/Tiny-RTC-I2C-modules-24C32-memory-DS1307-clock-RTC-module-without-battery-good-quality-low-price/2020927349.html) $0.53 AUD

* [LIR2032 rechargeable coin cell](https://www.aliexpress.com/item/2x-LIR2032-Rechargeable-Lithium-Li-ion-Batteries-3-6V-40mAh-Button-Coin-Cells-Battery-For-Watch/32842926682.html) $1.19 AUD



## Connections



STM32F407VET6 | TinyRTC I2C module

------------- | ----------------------

A9 (any pin)  | DS

A8 (I2C3 SCL) | SCL

C9 (I2C3 SDA) | SDA

3V3           | VCC

GND           | GND



## Links



* [micropython.org](http://micropython.org)

* [Binary-coded decimal](https://en.wikipedia.org/wiki/Binary-coded_decimal)

* [DS1307 datasheet](https://datasheets.maximintegrated.com/en/ds/DS1307.pdf)

* [AT24C32 datasheet](http://ww1.microchip.com/downloads/en/devicedoc/doc0336.pdf)



## License



Licensed under the [MIT License](http://opensource.org/licenses/MIT).