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Recommend me DAC...
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sonicdeejay



Joined: 20 Dec 2005
Posts: 112

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Recommend me DAC...
PostPosted: Sun Feb 19, 2006 9:14 am     Reply with quote

Guys,,,
I am from SIngapore and I can't seem to able to source a nice DAC DIP(not surface mount)for my project.1 output channel is good enough...I already looked for MCP492x,AD5301...
I am looking for DAC with 2wire(SDA,SDL) type..I don't really want i2C DAC as I don't have a sample code...

Any DAC to recommend...

thx??

sonic


Last edited by sonicdeejay on Sun Feb 19, 2006 10:27 am; edited 1 time in total
drh



Joined: 12 Jul 2004
Posts: 192
Location: Hemet, California USA

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PostPosted: Sun Feb 19, 2006 10:20 am     Reply with quote

Maxim makes DACs with the IIC interface.
www.maxim-ic.com
_________________
David
sonicdeejay



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PostPosted: Sun Feb 19, 2006 10:38 am     Reply with quote

drh wrote:
Maxim makes DACs with the IIC interface.
www.maxim-ic.com


bro..possibly not i2c,,becasue I don't have a sample code,,,
dyeatman



Joined: 06 Sep 2003
Posts: 1934
Location: Norman, OK

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PostPosted: Sun Feb 19, 2006 11:30 am     Reply with quote

You are ruling out I2C because no one will give you code and you don't want to try to figure it out yourself.... If I had set those kind of requirements most of my projects would have died long ago!

There is lots of code on this forum that shows how to use I2C so apparently you want someone to hand you exactly the code you want rather than put some effort into doing it yourself. Sometimes you have to bite the bullet and actually try... The process is called learning...
sonicdeejay



Joined: 20 Dec 2005
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PostPosted: Sun Feb 19, 2006 11:37 am     Reply with quote

sorry sir...my deadline jus too near...

Confused
sonicdeejay



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PostPosted: Sun Feb 19, 2006 12:34 pm     Reply with quote

Please allow me to re-write my question....

I need to output 2 differents digital values (e.g temp1 and temp2) from a PIC..so I don't think i can use i2c as it only cater for 1 output....

I am using PIC18F2525...

dyeatman



Joined: 06 Sep 2003
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PostPosted: Sun Feb 19, 2006 3:32 pm     Reply with quote

You CAN have multiple I2C devices on the same bus. Thats what the physical address pins on the chip and the address bits in the comm protocol are for. You need to do some reading and learn how I2C works before you dismiss it as unsuitable out of hand... Below is a link to a TI DAC device datasheet that has much of the information about I2C addressing etc...

http://focus.ti.com/docs/prod/folders/print/dac6573.html
Ttelmah
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PostPosted: Sun Feb 19, 2006 3:45 pm     Reply with quote

Fastest/simplest. Just use the two PWM outputs.
I2C, _does not_ just cater for one device.
The development time involved in driving an I2C device, is less than the time this thread has already been running.
You have not given enough data for anyone to really help much. What accuracy is needed?. What voltage range?. What update frequency?. etc. etc.
Seriously, sending two values this way, strikes as about the hardest/most inaccurate way possible to do this. You are going to suffer from noise, the inherent inaccuracies of both the ADC, and the DAC. etc.
I have used the MAX518 in the past, which is a dual DAC in one package. These are I2C, supporting up to four dual channel devices on one bus. The code to operate them is infantile, since they are 'receive only' devices. Just send the address, a command byte of zero for the first ADC, or one for the second, the value required, and a stop.
If you want greater accuracy, look at the MAX531. This uses SPI, and you could just add a single line with an inverter to enable one chip, and disable the other. Alternatively, using no extra lines, you can use these devices 'daisy chained', and then you can have multiple units connected in series, using no extra wires, and for twoo units just send a 32bit value, carrying the two 16bit values (12+4 dummy bits), for two devices.

Best Wishes
Sophi



Joined: 14 Jun 2005
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PostPosted: Sun Feb 19, 2006 5:24 pm     Reply with quote

If you really don't want to use i2C, try DAC0808. Very easy to use and cheap under $2 USD not surface mount.


*edit just saw u want 2 outputs. Sorry but DAC8080 only has one. But maybe something in its family has 2...

But I'm a total newbie and can tell you that i2C is pretty simple...CCS even has built in functions to make it happen.

SophE
sonicdeejay



Joined: 20 Dec 2005
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PostPosted: Sun Feb 19, 2006 7:45 pm     Reply with quote

Ttelmah wrote:
Fastest/simplest. Just use the two PWM outputs.
I2C, _does not_ just cater for one device.
The development time involved in driving an I2C device, is less than the time this thread has already been running.
You have not given enough data for anyone to really help much. What accuracy is needed?. What voltage range?. What update frequency?. etc. etc.
Seriously, sending two values this way, strikes as about the hardest/most inaccurate way possible to do this. You are going to suffer from noise, the inherent inaccuracies of both the ADC, and the DAC. etc.
I have used the MAX518 in the past, which is a dual DAC in one package. These are I2C, supporting up to four dual channel devices on one bus. The code to operate them is infantile, since they are 'receive only' devices. Just send the address, a command byte of zero for the first ADC, or one for the second, the value required, and a stop.
If you want greater accuracy, look at the MAX531. This uses SPI, and you could just add a single line with an inverter to enable one chip, and disable the other. Alternatively, using no extra lines, you can use these devices 'daisy chained', and then you can have multiple units connected in series, using no extra wires, and for twoo units just send a 32bit value, carrying the two 16bit values (12+4 dummy bits), for two devices.

Best Wishes



I am sending a value 0~5V from PIC1 to PIC2....as for accuarcy...the more the better...


If I am to use PWM,,I have no idea..how I can generate PWm represent the wave to raning from 0-5V and from the receiver how to interpreted as well...
sonicdeejay



Joined: 20 Dec 2005
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PostPosted: Sun Feb 19, 2006 7:59 pm     Reply with quote

dyeatman wrote:
You CAN have multiple I2C devices on the same bus. Thats what the physical address pins on the chip and the address bits in the comm protocol are for. You need to do some reading and learn how I2C works before you dismiss it as unsuitable out of hand... Below is a link to a TI DAC device datasheet that has much of the information about I2C addressing etc...

http://focus.ti.com/docs/prod/folders/print/dac6573.html


thx for the help...Sir...

Seem lik they are only avail in surface mount... Sad
Charlie U



Joined: 09 Sep 2003
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PostPosted: Sun Feb 19, 2006 8:18 pm     Reply with quote

There must be 10's if not 100's of different DACs with SPI and in a DIP package. It took me about 30 seconds to find a TI part: TLC5615.

http://focus.ti.com/docs/prod/folders/print/tlc5615.html

Try this one for a start.

Also try National, Linear Tech, Analog Devices, etc.
sonicdeejay



Joined: 20 Dec 2005
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PostPosted: Sun Feb 19, 2006 8:27 pm     Reply with quote

Charlie U wrote:
There must be 10's if not 100's of different DACs with SPI and in a DIP package. It took me about 30 seconds to find a TI part: TLC5615.

http://focus.ti.com/docs/prod/folders/print/tlc5615.html

Try this one for a start.

Also try National, Linear Tech, Analog Devices, etc.


aren't we looking @ i2C currenly,,,,

Anyway I jus got myself AD5311 http://www.analog.com/en/prod/0,,AD5311,00.html

any idea...it will suit my need?? Smile
Charlie U



Joined: 09 Sep 2003
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PostPosted: Sun Feb 19, 2006 9:06 pm     Reply with quote

I have no idea if this will suit your needs, because your original needs were a DAC in a DIP with SPI, now you have selected a DAC that is only available in SMT (MSOP and SOT23) and has an I2C interface. What exactly are your needs?
newguy



Joined: 24 Jun 2004
Posts: 1909

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PostPosted: Sun Feb 19, 2006 10:21 pm     Reply with quote

Charlie U wrote:
I have no idea if this will suit your needs, because your original needs were a DAC in a DIP with SPI, now you have selected a DAC that is only available in SMT (MSOP and SOT23) and has an I2C interface. What exactly are your needs?


From what I've been able to gather, his needs are to get someone to do his homework for him.
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