PIC16F887 and DS1307

[menta]

I've been reading all posts here regarding the DS1307 RTC, but I really can't get it to work.
I just get the value '0' when trying to read it.
Is soething in my code is wrong ?

	RTCSec var byte		' Seconds
	RTCMin var byte		' Minutes
	RTCHour var byte	' Hours
	RTCWDay var byte	' Weekday
	RTCDay var byte		' Day
	RTCMonth var byte	' Months
	RTCYear var byte	' Year
	RTCCtrl var byte	' Control 
	SetTime var byte	' 12/24 Hour Clock
	SetSec var byte		' Seconds
	SetMin var byte		' Minutes
	SetHour var byte	' Hours
	SetDay var byte		' Day
	SetMonth var byte	' Months
	SetYear var byte	' Year
	TimeOut var word	' Variable for SetUp Menu Time-Out
RTCSec=1
RTCMin=4

I2CWRITE PORTC.4,PORTC.3,$D0,$00,[RTCSec,RTCMin,RTCHour,RTCWDay,RTCDay,RTCMonth,RTCYear,RTCCtrl]
pause 100
main:
I2CRead PORTC.4,PORTC.3,$D0,$00,[RTCSec,RTCMin,RTCHour,RTCWDay,RTCDay,RTCMonth,RTCYear,RTCCtrl]
SEROUT PORTC.6,6,[254,1]
toggle PORTD.7 : pause 1000
SEROUT PORTC.6,6,[254,128,#RTCSec]
pause 1000
goto main

[skimask]

I've been reading all posts here regarding the DS1307 RTC, but I really can't get it to work.
I just get the value '0' when trying to read it.
Is soething in my code is wrong ?

A quick search on DS1307 will get you a long way. But since your SEARCH function seems to be broken, I'll show you use mine.
http://rentron.com/PicBasic/SERLED.htm
No, this code isn't 100% perfect for what you need, but I'll bet ANYTHING that you can easily modify for your purposes.

And besides, why are you trying to set the same time that you're trying to read?
If the set time is zero and the read time is zero, then it seems to me that your program, if that is the whole program, is working correctly.

Got any pullups on the I2C lines?

[menta]

Well, i write the time, then I keep reading it, isn't it suppose to be chance every second when I keep reading it ?
pullups, you mean resistors ? I tried, then I only got 16 or 32 instead of 0

[skimask]

Well, i write the time, then I keep reading it, isn't it suppose to be chance every second when I keep reading it ?

I don't know if it's supposed to chance every second, but if the clock is running, it may change every second.

pullups, you mean resistors ? I tried, then I only got 16 or 32 instead of 0

Complete this sentence:
The value of my resistors connected to +5v and to the I2C clock and data line is __________."

[menta]

The value of my resistors connected to +5v and to the I2C clock and data line is ____10k____."

..........

[amgen]

control register may need to be set

alsoooooo....
the I2c read and write address/control string have to be different, I just used binary 00011110 (just an example) to make sure the read write is correctly coded.

don

[menta]

tried that already. It doesn't help.
What do you mean by "the I2c read and write address/control string have to be different" ?

[amgen]

RTCADW CON %11010000 'DS1307 RTC ADDRESS SEND...RECEIVE
RTCADR CON %11010001

I2CWRITE SDA,SCL,RTCADW,7 ,%00010011 'TURN ON SQU WAVE OUT 32k HZ

I2CREAD SDA,SCL,RTCADR,0,[RTC[1],RTC[2],RTC[3],RTC[4],RTC[5],RTC[6],RTC[7]]


from my rtc stuff
don

[menta]

Ok, So I tried to use your example.
Still getting '0' when reading. If i use 10K resistors on the SDA and SCL I get '16'

INCLUDE "modedefs.bas"
    RTC     VAR BYTE[8] ' Data byte array

RTCADW CON %11010000 'DS1307 RTC ADDRESS SEND...RECEIVE
RTCADR CON %11010001 
SDA var PORTC.4
SCL var PORTC.3
pause 1000
I2CWRITE SDA,SCL,RTCADW,7,%00010011 'TURN ON SQU WAVE OUT 32k HZ

main:
;I2CREAD PORTC.4,PORTC.3,%11010000,$00,[RTCSec]
I2CREAD SDA,SCL,RTCADR,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

[amgen]

well,
data on 1307 is hex so.......

SEROUT2 PORTA.0,6,1,[ "_T" ,HEX RTC[6],"/",HEX2 RTC[5],"/20",_
HEX2 RTC[7]," , ",HEX RTC[3],":",HEX2 RTC[2],":",HEX2 RTC[1]," ",RTC[9],"M _" ]
( use your own port etc.)

the voltage on SCL & SDA (to gnd) has to be +5 at rest, no signal . Thats what the 10k resisters do.

also, you can check square wave out at 1 HZ with led/resister on the output pin of 1307 as visual check of rtc.
I2CWRITE SDA,SCL,RTCADW,7,%00010000 'TURN ON SQU WAVE OUT to...1... HZ

[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
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.

[skimask]

$EC is not a valid conversion requirement for this application.

My point was that there isn't any sort of error checking, flipped bits, logic errors, and so on...

[crisxstyle]

Hi!!!
I just wan't to know if its possible how i can set manualy the initial time of the clock using a bic basic code!i tried to do it but i found some problems due to bcd and hex code!
so there someone that do it?!?!

thank you so much

bye bye Cris

[skimask]

Hi!!!
I just wan't to know if its possible how i can set manualy the initial time of the clock using a bic basic code!i tried to do it but i found some problems due to bcd and hex code!
so there someone that do it?!?!

96 hits on these forums alone for ds1307...
Surely there's something in one of those threads to help you out...