SPI communication between the ADAS1000-3 and the Intel Edison platform

Hello,

thanks for your message.

One of the driver gurus here may be able to comment on your question related to Intel Edison (I don't know anything about it).

The selection of analog or digital mode is your call. The noise performance is marginally better in analog mode. Aside from that you will get the same Lead result from the ADAS1000.

best regards,

Catherine.

Ok, perfect.

Thanks.

ADAS1000 requires a standard serial interface, so any platform that has such a peripheral will be perfect. We don't have experience with Intel Edison, but at first glance, it seems to be compatible.

Dragos

This should be a question for CatherineR.

Thanks,

Dragos

Thanks DragosB

This is my schematic for ADAS1000-3

Could you please check if everything looks good. I plan to use only 3 electrodes, 2 electrodes and one for the right leg.

Thanks.

Again I want to clarify a doubt CatherineR

I'm finalizing the design of the PCB, before sending it to manufacture I want to check that at hardware level everything is fine. I'm going to put the schematic diagram here so please give me your opinion.

I already checked that the adas1000-3 works with Intel Edison and it does, and I found a project that shows this.
My doubt lies in the DRDY pin. I must leave this pin without connection or pin to connect it, in case I do not finish understanding the function of this pin in the SPI communication.
I still do not work in software development, but I want to first check that the hardware is functional.
I appreciate your input and comments.

Best regards

Hello,

Thanks for update, glad to hear you are running with the Intel Edison.

Comments on the schematic as follows:

1. Decoupling on IOVDD: Should be local/close to the ADAS1000 pins. 0.01uF on each pin and one 4.7uF shared.
2. Decoupling on AVDD: Should be local/close to the ADAS1000 pins. 0.01uF on each pin and one 4.7uF shared.
3. REFOUT – schematic shows 2x0.1uF, recommend 1x0.1uF + 1x10uF close to the pin
4. XTAL caps – recommend reducing value to 10pF. Datasheet being updated to reflect this. Note on EZ here
   1. https://ez.analog.com/docs/DOC-16851-adas1000-crystal-oscillator-startup
   2. What crystal is being used?
5. Use the RESET pin?
6. DRDYb - I would recommend connecting this to your controller, that will give you options. Let me know if you have questions about how it works.

Hello

Thanks for response.

1. IOVDD - 2x0.01uF ok. (there are only 2xIOVDD pins)

2. AVDD - 4 x 0.1uF ok (there are 4 xAVDD pins - located in different areas, for your layout, place one cap close to each pin).

4. The ESR of that crystal is quite high. Do you have any data from the manufacturer as to what the typical ESR performance is (sometimes manufacturers will provide this if you ask)? Also the surface mount pads look quite large - the layout footprint will add some more capacitance. To avoid start-up issues, I would suggest load cap of 10pF, but you may need to go even lower.

5. Not sure what you mean? It may be a good option to connect the reset pin to a pin on the controller - like a gpio.

6. the DRDYb operates from IOVDD voltage level - same as the other SPI pins.

hope that helps.

best regards,

Catherine.

Hello CatherineR  thanks for update. I appreciate.

According to the corrections that you indicate, I will place the following:

1. Decoupling on IOVDD: I must use 2 capacitors of 0.01uF or I can use 4 (0.01uF).

2. Decoupling on AVDD: I must use 2 capacitors of 0.01uF or I can use 4 (0.01uF).

3. I will make the suggested change 

4. The crystal that I´m using is the following: ABM3-8.192MHZ-B4Y-T

5. In the case of using the reset I can use any configuration?

6. I'm going to connect the pin DRDYb to the Intel Edison. Which voltage level handles this pin?