Pages: [1]   Go Down
Author Topic: Any experience with this ADC? PCM1850A PCM1851A  (Read 1515 times)
0 Members and 1 Guest are viewing this topic.
Peoples Republic of Cantabrigia
Offline Offline
God Member
*****
Karma: 6
Posts: 719
Arduino happiness
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

I took a brief interest in this ADC due to its low cost and high performance. For example, it could be really nifty for power measurements since it offers oodles of sampling speed, a built-in PGA, 6 channel MUX for each of the two built-in 24-bit ADCs, etc.) All in a package that has a reasonable cost and which which can be interfaced with easily via I2C.

But the documentation could be better and one aspect in particular has me stumped: Although this is a unipolar ADC design, it does not allow DC inputs. All external pins require a de-coupling pin but there is no differential input as I would have expected. How is this supposed to work?
Logged

0
Offline Offline
Shannon Member
****
Karma: 200
Posts: 11718
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Its an I2S bus audio ADC, needs 3 accurate clocks, don't even think about interfacing an Arduino to it!

The lowest rate it can handle is 16kHz sample rate 64 bit clocks per sample,  ie 1024kb/second (and you have to feed it an 4.096MHz clock).  I've interfaced to I2S devices on the Propellor microcontroller but that has 16 clock units each with a phase-locked-loop and capable of 40MHz...

Don't confuse I2C and I2S.

All these I2S devices are for audio, they all do high-pass filtering to remove the DC component.
Logged

[ I won't respond to messages, use the forum please ]

Peoples Republic of Cantabrigia
Offline Offline
God Member
*****
Karma: 6
Posts: 719
Arduino happiness
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Silly me. I saw the reference to I2S as well but when the datasheet mentioned that the device could be configured using I2C, I thought it might work. I have since realized that while one might be able to configure the unit via I2C (PCM1851A) or SPI (PCM1850A) that the output is still  I2S since there are no registers to query.

Thanks for the help!
Logged

Pages: [1]   Go Up
Jump to: