I need help with i2c memory

[DynamoBen]

Make your addr a word variable, not byte.

Also make sure you assign a value to your addr before the write command.

Example:

Addr=3
I2Cwrite sda,scl,contW,addr,[x] 'should write 3 to address 0, right?'
pause 10

Finally you may want to add DEFINE I2C_SLOW 1 if things are still not working.

Basically if your wired like the manual says and you do the above it works great.

[NavMicroSystems]

Try this:

addr var word
sda var PORTB.0
scl var PORTB.1
cont con %10100000
x var byte 'test data'
addr=%00000000
x=3 'test data is the number 3'

I2Cwrite sda,scl,cont,addr,[x] 'should write 3 to address 0, right?'
pause 10
I2Cread sda,scl,cont,addr,[x] 'should read the data'
pause 10
serout Portb.2,4,[DEC x] 'displays data on an LCD'


end

[DynamoBen]

Also keep in mind if your hoping to see the number three on the LCD you will need to modify your code a bit.

serout Portb.2,4,[DEC x] 'displays ASCII version of data on an LCD'

[-c3-]

Try this:

addr var word
sda var PORTB.0
scl var PORTB.1
cont con %10100000
x var byte 'test data'
addr=%00000000
x=3 'test data is the number 3'

I2Cwrite sda,scl,cont,addr,[x] 'should write 3 to address 0, right?'
pause 10
I2Cread sda,scl,cont,addr,[x] 'should read the data'
pause 10
serout Portb.2,4,[DEC x] 'displays data on an LCD'


end

when i go to compile i get "bad expression" on serout Portb.2,4,[DEC x]
i am using microcode studio.

[DynamoBen]

You are missing the two pull-up resistors that are required.

Try wiring it identical to the Melabs user manual. This is your best shot at getting it to work. I have included the drawing in this post.

[-c3-]

You are missing the two pull-up resistors that are required.

Try wiring it identical to the Melabs user manual. This is your best shot at getting it to work. I have included the drawing in this post.

you are talking about the 2 pull up resistors on scl and sda correct? they are there. as far as i can tell the only difference between what i have and your picture is the cap from vdd to ground on pin 14. ill put that in and see what happens..

[DynamoBen]

You may want to wire it exactly like the drawing for testing purposes.

[-c3-]

alright, ive spent some more time on this, with my new lcd. redid the circuit to the schematic posted, still not working for me, it seems it is not writing at all,

do i need to set trisb to something? thats my current line of thought,
thx

[mister_e]

when i go to compile i get "bad expression" on serout Portb.2,4,[DEC x]
i am using microcode studio.

what about serout Portb.2,4,[#x]???

[-c3-]

what about serout Portb.2,4,[#x]???

that compiles, only problem now is i killed my lcd...... needless to say, from now on i will be a little more careful of which voltage supply i am using.... little puffs of smoke are bad....

[-c3-]

Tried that, still nothing. it makes me wonder if there is something with my circuit i am missing...(i think it is right...)

if any one wants to check the wiring (its not messy)
chip pinouts included

http://www.siue.edu/~bluttin/circuit.htm

thanks

the middle chip is the uln2803, its just driving the leds, ive tried it connected, and unconnected.