Originally Posted by
Melanie
... And what about $00 - what's it there for? The answer is screaming at you from the pages of the PBP Manual description of the I2C Command, and the DS1307's Datasheet. The two of them go together hand-in-hand.
Mel,
Bear with me on this as I'm sure quite a few of us still have difficulties in getting our heads round bits and bytes and registers etc. But to try and answer your question and see if I've got some grips with the data sheet, here's my take on the above.
$00 is the start of the register address (00H). This byte stores the seconds, bits 0-4 for the digits and bits 5-7 the 10's. The next byte (01H) is the same but for mins. 02H stores the hours, with bit 6 setting the device up for 12/24 hrs depending if set high or low. Bits 0-2 of 03H stores the days, 04H date, 05H month, 06H year (1st 4 bits for digits, last 4 bits decades).
The only part I don't grasp is the $D0 part - The manual stated
I2CREAD DataPin,ClockPin,Control,{Address,}[Var{,Var...}]{,Label}
so in the code I have
Code:
I2CRead SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour,RTCWDay,RTCDay,RTCMonth,RTCYear,RTCCtrl]
which transpires as datapin, clockpin, then control. but the only control reference I can find in the data sheet is for SQW (square wave out), and I'm still at a loss as to where you arrive at the $D0
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