Re: [avr-gcc-list] AVR and external ADC

[Joerg Wunsch]

"Brandon Tolbert" <address@hidden> wrote:

> This is a multi-part message in MIME format.

(Please don't post HTML.)

> I have an old 8 bit 4 channel TI adc0834acn ...

> My question is do I have to provide those clock cycles =
> myself by taking clk high and low 8 times or is it internal and I just =
> have to use the clk when inputting or receiving data serially?

Nope, if you read the datasheet of the ADC083x carefully, you'll see
that you have to provide that clock externally to the ADC.  Of course,
the actual clock source is your design decision.  The datasheet says
that the clock frequency must be not more than 400 kHz, so you can't
use the MCU clock directly.  You can either use a timer channel to
externally provide the clock, you can toggle an IO pin manually (where
you need to ensure the timing yourself), or maybe you could even
program the SPI appropriately.

> I am very =
> new to AVR and microcontrolers this is even my first project.

Well, except for possibly using the SPI to generate the clock, the
remainder isn't AVR-specific at all.

-- 
J"org Wunsch                                           Unix support engineer
address@hidden        http://www.interface-systems.de/~j/
avr-gcc-list at http://avr1.org