Ds3231 rtc usage

[gunayburak]

Let me get this straight ...

A read op from DS3231 must be in this form I think ...

i2cREAD SDA,SCL,%11010001,$00,var

Am I mistaken ?

[richard]

from the book

I2CREAD DataPin, ClockPin, Control,{Address,}[Var{,Var...}]{,Label}

[gunayburak]

from the book

Indeed from the book yet not PBP's but DS3231's ... Obviously you haven't seen the number written in different format in my message .. Observe the bold formatted number .. The slave address + direction bit ...

[richard]

again
from the book (i2cread)

The upper 7 bits of the


Control byte contain the control code along with chip select
or additional address information, depending on the particular device. The low
order bit is an internal flag indicating whether it is a read or write command and
should be kept clear.

[gunayburak]

again
from the book (i2cread)

So there is no use of the lsb of the control bit , then it's determined by the command's itself ... I mean if it is I2CREAD op then it automatically determines this bit itself ... Am I correct ? I'll give it a try once more by using

i2cREAD SDA,SCL,%11010000,$00,var

At least I may read the control or the status register ...

Thanks ..

[gunayburak]

So there is no use of the lsb of the control bit , then it's determined by the command's itself ... I mean if it is I2CREAD op then it automatically determines this bit itself ... Am I correct ? I'll give it a try once more by using

i2cREAD SDA,SCL,%11010000,$00,var

At least I may read the control or the status register ...

Thanks ..

No luck with that either ... I have even pulled the scl and sda up with 4.7 k resistors ... neither I can write nor read the control and status registers ... 😕

[MichelJasmin]

I don't want to be rude but RTFM, p.156:

The Address size sent (byte or word) is determined by the size of the variable that is used. If a byte-sized variable is used for the Address, an 8-bit address is sent. If a word-sized variable is used, a 16-bit address is sent. Be sure to use the proper sized variable for the device you wish to communicate with. Constants should not be used for the Address as the size can vary dependent on the size of the constant. Also, expressions should not be used as they can cause an improper Address size to be sent.

Pull-up resistors are mandatory for I2C. Keep trying, the DS3231 has nice features like alarms and is more accurate than the DS1307.