Re: Simple multi-channel serial ADC (8-ch)?

Rene Tschaggelar wrote:

Joerg wrote:

Hello Folks,

As an analog guy I get goose pimples when I see converters like the TLV1508. Impressive performance but, boy, do they need a complicated liturgy to get data out of them. Many of them must be told via SPI that I want to read this, that and the other value. Then you must patiently wait x clock cycles, wasting away bus time. The guy who designs the host processing will throw his coffee mug at me because there'll be a dozen of these.

Here is what I am looking for: 10 bits or so, 8 channels, bone-simple readout, can very very slow, low kHz range. All I need is to read DC values and it doesn't matter when the exact sampling time was. SPI, I2C, anything serial works. I mean, with a FIFO in there they should be able to do continuous autoscan and just dump the last valid set of values upon request.

Any ideas? I am also looking for 10-12 bit DAC with lots of channels but that seems to be much simpler.


Joerg,
I'd employ a controller such as the AVR Tiny26 with 8
differential or 11 single ended 10 bit channels.
Since you need a dozend of them just hook them together
with an SPI or an USI.


I wanted to avoid a uC on there because it wouldn't be needed for any other purpose. They are too slow for the analog stuff I am doing on the boards. The ADCs on uC also tend to be noisier than stand-alone chips. Of course I could set up the uC to do autoscan and chips like the MSP430F2xxx have that feature in hardware. All you need to do is set one bit in a register upon initialize. Beats me why stand-alone ADCs don't have that. That way the host wouldn't have to talk, just enable CS via the correct address on the bus and then read the stream.


Linear Tech has a a bunch of multichannel DACs with the
LTC2600 : 8x 12 bits for 9$ as example.


Thanks, that could be a good one. I am currently leaning towards the TLV56xx series. It all depends what's in stock because that is an indicator of popularity, and sometimes of longevity as well.

--
Regards, Joerg

http://www.analogconsultants.com
.

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