DAC716, two wire operation

[Theo Hogers]

Hi again.
Sorry for the misspelings in the original message, it might confuse you,
the noted ISP interupt should read SPI interupt.

theo.

----- Original Message -----
From: Theo Hogers <t.hogers at home.nl>
To: Roel Das <Roel.Das at student.groept.be>; Synth DIY
<synth-diy at node12b53.a2000.nl>
Sent: Saturday, March 11, 2000 12:23 AM
Subject: Re: DAC716, two wire operation


> mmm . . I can be mistaken, but it looks like a 3 wire SPI interfase to me.
> The only snatch seems to be the A0 and A1 lines, see figure 1 on page 7 of
> the data sheet.
> When A0 is low serial data is loaded in the input latch.
> When A1 is low the bit pattern in the input latch is loaded parralel in
the
> DA latch.
> Thus when you load data while both are low you end up with fantastic
low-fi
> FX.
>
> Best way to connect this seems to me over SPI and use the ISP ready
interupt
> to activate A1.
> Take a peek in the AVR documentation.
>  A0 is SS\, SDI is MOSI and SDO is MISO, so far i understand it the clock
> polarity bit (CPOL)
> must be set to 1 to get the correct clock signal.
> The only problem is that you need a clock pulse to get the 716 respond to
> the low level on A1.
> Chancing the CPOL bit to zero and back should do the trick.
>
> Note that i didn't test this, just reading the documentation.
> (:-) pure self intrest by the way, your not gona use it to do CV control
'n
> stuf are u. (well I am.)
>
> Cheers Theo
>
> ----- Original Message -----
> From: Roel Das <Roel.Das at student.groept.be>
> To: Synth DIY <synth-diy at node12b53.a2000.nl>
> Sent: Friday, March 10, 2000 4:18 PM
> Subject: DAC716, two wire operation
>
>
> > Hello again,
> >
> > I've been looking at the datasheets of BurrBrowns DAC716. This device
> allows
> > a two wire operation. When using this mode, is the d/a latch always one
> bit
> > behind the input shift register, or is it as if the latch disabled when
> both
> > Ao and A1 are connected to ground? It says in the datasheet (p3, the
truth
> > table) that using two wire operation, all digital input changes will
> appear
> > at the output, but it doesn't say anything about the timing. If you
clock
> in
> > 16bit, do you need another clock pulse to get the correct output, or is
> the
> > output directly available after you clock in the 16th bit?
> > Anyone knows this?
> >
> > Datasheets etc can be found at:
> >
>
http://www.burr-brown.com/cgi-bin/WebObjects/BurrBrown.woa/wa/displayProduct
> > Folder?productName=DAC716
> >
> >
> > Thanks!!
> > Roel
> >
> >
>
>