PIC16F887 and DS1307

[skimask]

PBP handles the R/W bit for you just like it says in the manual...so...

INCLUDE "modedefs.bas"
RTC VAR BYTE[8] ' Data byte array
RTC CON %11010000 'DS1307 RTC ADDRESS SEND...RECEIVE
SDA var PORTC.4
SCL var PORTC.3
pause 1000
I2CWRITE SDA,SCL,RTC,7,%00010011 'TURN ON SQU WAVE OUT 32k HZ
main:
I2CREAD SDA,SCL,RTC,0,[RTC[1],RTC[2],RTC[3],RTC[4],RTC[5],RTC[6],RTC[7]]
SEROUT PORTC.6,6,[254,1]
toggle PORTD.7 : pause 1000
SEROUT PORTC.6,6,[254,128,#RTC[1]]
pause 1000
goto main

[menta]

well,
I can't get any signal on the SWQE output, not by LED or by the logic analyzer of the PICkit2. So I might guess the 1307 is malfunctioning.
This is what I get when analyzing the SCL vs SDA

This is what I get when analyzing the SCL vs SWQ

This is what I get when analyzing the SCl vs SDA

[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
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