i2c with a dac

[fabritio]

Hello,

I am quite new in picbasic programming.
I am trying to figure out if it's possible to send bits to a dac (tc1321) form a pic16f876.
I want to send a 10bit serial word to the device.
I wrote this program:


SDA var byte
SCL var byte
ADDR var byte
VAL var word
i var word

TRISB.4 = 1 ' Pin B4ingresso
TRISC = 0 ' Porta C uscita

SDA = 12 ' Imposto l'uscita SDA sul pin C4
SCL = 11 ' Imposto l'uscita SCL sul pin C3
ADDR = %10010000 ' Indirizzo del TC1321

main:

if PORTB.4 then
goto inizia
else
goto main
endif

inizia:

val = %0000000000
for i=0 to 14
i2cwrite sda,scl,addr,[val]
val = val + %1000000
next
val = %1111111111
i2cwrite sda,scl,addr,[val]
while PORTB.4 = 0
i2cwrite sda,scl,addr,[val]
wend

goto inizia
end

Do you think it's right or I've done GREAT errors?
Thank you very much!!

Fabrizio

[fabritio]

Originally posted by Acetronics
Hi,

I suppose it might have been this

for i=0 to 14
i2cwrite sda,scl,addr,[val]
val = val + %0000001

instead of that

for i=0 to 14
i2cwrite sda,scl,addr,[val]
val = val + %1000000

.....

or there's no need for a DAC.

Alain

I only meant to do a conversion from 0 to 1024 in 16 steps, so I add 64 for every step (%1000000).
Thank you for the answer however...

[Acetronics2]

Hi

I undertand ...

But, you're sending a 16 bits word for 10 needed bits ...

is that a problem with the DAC ???

Alain

[fabritio]

So, how can I define that I am sending only 10 bits?

[fabritio]

Is there a configuration of the SSP registers that I have to do first?

[mister_e]

Originally posted by fabritio
So, how can I define that I am sending only 10 bits?

i2cwrite sda,scl,addr,[val\10]

[fabritio]

Thank you,
i am still wondering about the ssp registers configurations....

[Acetronics2]

Did you had a look at table 4-4 page 10 from the TC Datasheet ???
Seems that the 6 lower data bits must be 0, and 16 bits to be sent.
so your example gives the 2 to 16 lower values ( less than 4% of full output ... )
that at a very high speed , as there is no PAUSE between each FOR-NEXT ... and then jumps and stops to the max value.
output seems not to be clearly visible ... even on a good scope !

Alain

[Bongo]

Please send me working Basic code for TC1321 ...

[Melanie]

Gesh... try this thread...

http://www.picbasic.co.uk/forum/showthread.php?t=1498

[NavMicroSystems]

Bongo,

great start on this forum!

here is your welcome gift

[scholar]

@ device hs_osc
define osc 4

Ctrl con %10010000

CPIN var portb.1
DPIN var portb.0

trisa=0
porta=255
pause 1000
porta=0
pause 1000' Pause 50ms for MC23016 to start-up



main:
i2cwrite DPIN, CPIN, Ctrl,%00000000,%10000000,%00000000 '512*Vref/1024
pause 2000
i2cwrite DPIN, CPIN, Ctrl,%00000000,%00000000,%00000000
pause 2000
goto main





with this code i able to generate analog voltage at the output. But funny thing is i only able to generate the first value (512*Vref/1024) but no respond after 2s. It suppose to change to 0V after 2s.