PIC16F887 and DS1307

[Bruce]

Here are a few things that 'may' help;

1. If you're using an oscillator >8MHz, then you'll want to include DEFINE I2C_SLOW 1
since the 1307 max clock speed is 100kHz.

2. The SQW output is an open-drain type. I.E. it cannot output a logic 1. Use a 10K
pull-up on the SQW output. Then you should see a square wave output on your scope.

3. Use the external pull-ups on SDA and SCL.

4. Connect a 3V battery to the 1307 Vbat input.

[menta]

non of the above really helps.
Probably the 1307 is dead.

[menta]

I replaced the DS1307 with VS1307 which seems to work.
Is there any other way to convert the data to dec other than:

I2CRead SDA, SCL, $D0, $00, [A]
Sec1=(A.0*1)+(A.1*2)+(A.2*4)+(A.3*8)
Sec10=(A.4*1)+(A.5*2)+(A.6*4)

[menta]

Now I need to understand how to convert from decimal (which comes from the user setup) to write to the RTC chip.

[menta]

Found it
ConvertBCD:
CounterB=CounterA DIG 1
CounterB=CounterB<<4
CounterB=CounterB+CounterA DIG 0
Return

[skimask]

Found it

What happens if CounterA = $EC?

[Melanie]

We're talking about a DS1307 RTC here (and ignoring the MSB of certain Registers) where the only valid individual digits are in the range 0-9. The subroutine converts two digit DECIMAL in the range 0-99 to a single BCD Byte. $EC is not a valid conversion requirement for this application.