problems with I2C.... and ideas why dosent work?

[snood]

okay, ive added in the pullup resistors, ive ensured everything is connected to the correct things, ive made sure that i am addressing correctly, as far as i can see, i'm doing everything as i should.... now when i try set the time/dats as above and then read it back i get the values "16"

this is also true of the i2C EEPROM i am using on the same bus.

any ideas?

Snood

edit: i just thought that the value 16 is a hex "F" any ideas?

[NavMicroSystems]

Snood,
this is a perfect time to have a look at the datasheet and the examples you have got.

If you are expecting any further assistance post your schematic and code.
(please cut the code down to the minimum required for reading writing the RTC / EEPROM)

But before posting please do some reading!

[snood]

please..... i have read the data sheet over and over again, ive read various places about I2C and i have studied the sample codes that i have been pointed to and still not a clue


TRISB = %11111111

second VAR BYTE
minute VAR BYTE
hour VAR BYTE
day VAR BYTE
date VAR BYTE
month VAR BYTE
year VAR BYTE

ITCDEVICE VAR BYTE
ITCADDRESS VAR WORD

SDA VAR PORTC.4
SCL VAR PORTC.3

ITCDEVICE = $D0
ITCADDRESS = $00

second = 0
minute = 0
hour = 12
day = 2
date = 25
year = 5

I2CWrite SDA, SCL, ITCDEVICE, ITCADDRESS, [second, minute, hour, day, date, month, year]

Pause 500

I2CRead SDA, SCL, ITCDEVICE, ITCADDRESS, [second, minute, hour, day, date, month, year]

at this point i dend the variables to my LCD and what comes up on the screen is "16"

thanks

Snood

edit: it's been suggested to me that as i'm recieving "16" or a single "f" that maybe something is holding the data line up? still clueless other than that

[NavMicroSystems]

ITCADDRESS VAR WORD

the RTC requires a BYTE address, not WORD !

second = 0
minute = 0 
hour = 12
day = 2
date = 25
year = 5

I2CWrite SDA, SCL, ITCDEVICE, ITCADDRESS, [second, minute, hour, day, date, month, year]

1. there is no explicit value in "month"

2. the RTC uses BCD format, the decimal values you are writing to the RTC don't make much sense.
-----
Now it's up to you to find out what the correct format would look like.

it's been suggested to me that as i'm recieving "16" or a single "f" that maybe something is holding the data line up? still clueless other than that

without a schematic we can't help
You have already got more information than you would ever need to solve this problem.

Do some work on your own.

[snood]

the pic will automaticaly transmit the numbers in BCD.... even mel uses just regular numbers... and the missing month value is just a typing error, it is infact in my program.

a direct quote from the DS1307 datasheet:

"After the DS1307 acknowledges the slave address + write bit, the master transmits a word address to the DS1307."

WORD address

as fror the schematic... it's connected in the same fassion as the typical operating citcuit in the datasheet with 4k7 pullups... the Square wawe pin is just left hanging as i'm not using it.

please stop telling me to do my own work... the questions i ask are simply what i cant find myself so i'm calling upon the expertese of other people. if you dont know how to solve my problem then just say so.

Snood

[NavMicroSystems]

This DOES work:

I2CWrite SDA, SCL, $D0,0, [second, minute, hour, day, date, month, year]

Pause 500

I2CRead SDA, SCL, $D0, 0, [second, minute, hour, day, date, month, year]

what more do you want?

we can't fix your hardware remotely.

the pic will automaticaly transmit the numbers in BCD....

WOW, that's great, so I can save a lot of codespace by removing all those conversions from my programs and let the PIC do it on it's own.
But how do you tell the PIC what format you want/need?
(or is there some kind of "Do What I Mean" Wizzard I didn't know about yet?)

please stop telling me to do my own work...

OK, there will be silence on this thread now...

[Archilochus]

Hi snood,
Odd... You've got this:
a direct quote from the DS1307 datasheet:
"After the DS1307 acknowledges the slave address + write bit, the master transmits a word address to the DS1307."

I can't find that quote at all in my 1307 data sheet. Mine says this:
"The DS1307 operates as a slave device on the serial bus. Access is obtained by implementing a START condition and providing a device identification code followed by a register address."

"device identification code" and "register address" are both bytes.
My code works fine with bytes for both items.

Are you certain you're reading a 1307 data sheet - sounds more like the sheet for the 1340?

Arch