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Forum: Analog Circuits Convert Analogue DC to SENT


Author: Sergii (Guest)
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Hi, we have a task to convert Analogue DC signal (5V max) to SENT 
protocol.
Therefore we are looking for AD converter with 2 Analogue inputs and one 
Digital output.
Can someone advise any suitable options?

Author: derguteweka (Guest)
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Moin,

My knowledge of the SENT protocol is rather low, just what's on 
wikipedia - but from that, i'm pretty sure, that an attiny13a should be 
able to suit your needs.
BUT: looks like you'll need some real-time-assembler software writing 
skills...

Gruss
WK

Author: Sergii L. (Company: TUM) (sergii)
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Servus WK,

should we keep it English, so that we can add some non-English speaking 
guys in the discussion? =)
Yes, you are right, SENT is quite rare and basically used for automotive 
sensor. Unfortunately, I have some basics skills of signal processing 
only (mainly with LabView FPGA), so real-time-assembler sounds 
frightening.
I made a brief research on the topic, do you think something like this 
will suite the task? -> http://www.ti.com/product/ads8350

Author: derguteweka (Guest)
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Moin,

Looks like the ADS8350 is a dual channel ADC with SPI output. So you 
might use it as an Analog-to-SPI Converter, but you'll still need 
another chip to convert SPI to SENT. So this other chip would have to do 
the "hard part" (the SENT timing, framing, calculation of checksums, 
communication via SPI, etc).

Depending on your real needs, the ADS8350 might be even a little bit to 
much - do you really need 16bit resolution at 750kSamples/sec with 
simultaneous sampling?
Usually people asking for advice just believe they'd urgently need the 
16bit resolution. But developing hardware to use the full 16bit range is 
not at all a simple task. Layout recommendation in the datasheet is not 
just because of the colorful pictures...
En plus: are you able to solder the itsy bitsy tiny 3x3mm 16pin package 
with the exposed thermal pad?

Gruss
WK

Author: Anja (Guest)
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Hello,

usually SENT has 2 (main) channels with 12 Bit values so no need to use 
a 16 Bit ADC. A ATTINY with 10 Bit ADC might be also not suitable.

Typical frame rate is around 1ms for the complete frame. So a few kS/s 
will be sufficient.

I would use a PIC24FV32KA301/PIC16F184XX or similar with 12 Bit ADC for 
this.

regards

Anja

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