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

[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

[snood]

i got the datasheet here: http://pdfserv.maxim-ic.com/en/ds/DS1307.pdf

under the "Slave Receiver Mode (Write Mode)" section of page 11

also on page 12 the data diagram shws a word address.

this is highly confusing.

Snood

edit: equaly it says: The DS1307 operates as a slave device on the I2C bus. Access is obtained by implementing a START
condition and providing a device identification code followed by a register address.

not "serial" but "i2c"

are you looking at an old version maybe?

[NavMicroSystems]

Hi Arch,

Snood has got more than one tested and working examples.

If one doesn't accept that 8 bits make a byte
and 16 bit make a word
and decimal 25 is different from hex 25
there is nothing we can do in addition.

[Archilochus]

Just down-loaded the sheet in your link, and it is different than the one I got from Maxim's site on March 19 of this year.

The "I2C" vs "serial" wording I think was just due to some patent / copyright issues.

Since the 1307's register map only goes to $3F, writing a WORD for the register address probably causes problems. Use a BYTE instead - works for me!

Arch

[snood]

thanks Arch

where did hex come into the equation ralph? the calender is written in BCD so what's wrong with using 25 in the variable as PBP will just convert it into 00011001 if i defined the data as $25 then yes... i would be trying to use hex which would of course give 100101 or 37 decimal. but i AM using decimal so thats no problem

who said that i was denying that 8bits = byte and 16bits = word? i didnt

please refrain from being so scathing and be polite like Arch

thankyou

Paul