hello and good day. i just starting to learn on how to design my own r4 with clock that i can display using an lcd. based from my schematic and another one from ds3231 datasheet for pin description, the I2C can communicate using 5v, but can i know why another design from adafruit is using 3.3v. can anyone explain to me what im doing wrong please
According to the datasheet, the part works with a supply voltage of 2.3 to 5.5 volts.
It has a 3V coin cell to power the unit when the supply voltage is removed.
According to this page from Adafruit, you would use the same voltage that the microcontroller logic is based on.
The UNO R4 WiFi is a bit unique, it has both a 5V I2C bus and a 3.3V I2C bus. The 5V bus, Wire, is on the SCL/SDA pins and the corresponding analog pins. The 3.3V bus, Wire1, is on the QWIIC connector. The QWIIC connector is compatible with Adafruit's STEMMA QT connector.
If you have wifi access to the internet, you can get the time from an NTP server and keep accurate time without an external RTC.
that give me an idea. thing is, im trying to make a shield and make an alarm clock with buzzer and 2004 lcd. If the QWIIC connector have that 3.3v I2C, that mean i just need to make a connector and jump from the uno to my shield.
I can do that? how do i connect to NTP server and keep accurate time without external RTC @david_2018?
I had been doing some digging on how to use this particular IC. it also tells me that I need to tie the Vbat to ground if im not using a battery, same with the unused pin.