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Feather accelerometer, RF transmitter, data logging project.
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Re: Feather accelerometer, RF transmitter, data logging proj

by wahleworld on Sat Dec 22, 2018 6:02 pm

The RAM on the feather M0, will it keep data if power is lost? What about the FRAM breakout?

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Re: Feather accelerometer, RF transmitter, data logging proj

by adafruit_support_bill on Sun Dec 23, 2018 6:53 am

The RAM on the M0 is volatile. It will not retain data through a power cycle. The FRAM is non-volatile.

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Re: Feather accelerometer, RF transmitter, data logging proj

by wahleworld on Tue Jan 01, 2019 2:26 am

Is there an ideal pin choice for an accelerometer and FRAM breakout attachment? I'll be soldering them to a protowing eventually.

I'm currently looking at the pint out guide and am trying to decide.

Any input is appreciated!

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Re: Feather accelerometer, RF transmitter, data logging proj

by adafruit_support_bill on Tue Jan 01, 2019 8:15 am

The LIS3DH has an i2c interface, so you will want to use the hardware i2c bus on the M0. That is on pins 20 & 21 (SDA & SCL).
The FRAM board has an SPI interface, so the hardware SPI pins are the way to go: GPIO 24, 23 & 22 (CK, MOSI & MISO)
You will also need one more GPIO pin for CS on the FRAM. You can use any available GPIO pin.
https://learn.adafruit.com/adafruit-fea ... c-pins-2-8

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Re: Feather accelerometer, RF transmitter, data logging proj

by wahleworld on Tue Jan 01, 2019 1:44 pm

Thank you.

What are all the acronyms for the pins? Is there somewhere where I can begin to decipher what all of the wording means on a pinout diagram?

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Re: Feather accelerometer, RF transmitter, data logging proj

by wahleworld on Tue Jan 01, 2019 1:51 pm

If I'm using the feather M0 RFM9 do I need to be concerned with the MOSI and MISO pins connected for the FRAM? I'm still learning all of this lingo. Thanks in advance!
Last edited by wahleworld on Tue Jan 01, 2019 2:20 pm, edited 2 times in total.

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Re: Feather accelerometer, RF transmitter, data logging proj

by adafruit_support_bill on Tue Jan 01, 2019 2:00 pm

Here are a couple of good introductions to the SPI and I2C interface buses:

http://www.circuitbasics.com/basics-of- ... n-protocol
http://www.circuitbasics.com/basics-of- ... -protocol/

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Re: Feather accelerometer, RF transmitter, data logging proj

by wahleworld on Wed Jan 02, 2019 1:24 pm

If I'm using the feather M0 RFM9 do I need to be concerned with the MOSI and MISO pins connected for the FRAM? I'm still learning all of this lingo. Thanks in advance!

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Re: Feather accelerometer, RF transmitter, data logging proj

by adafruit_support_bill on Wed Jan 02, 2019 1:54 pm

do I need to be concerned with the MOSI and MISO pins connected for the FRAM?

MOSI is "Master Out Slave In". You need that if you want to write data to the slave device (the FRAM).
MISO is "Master In Slave Out". You need that if you want to read data from the slave device.

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Re: Feather accelerometer, RF transmitter, data logging proj

by wahleworld on Wed Jan 02, 2019 5:04 pm

I'm wondering how the MISO and MOSI work. Would I be able to send an RF signal to a nearby alarm station, while writing data to the FRAM? or would it have to be in succession?

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Re: Feather accelerometer, RF transmitter, data logging proj

by adafruit_support_bill on Wed Jan 02, 2019 5:34 pm

The M0 is a single-core processor. It can only do one thing at a time.

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Re: Feather accelerometer, RF transmitter, data logging proj

by wahleworld on Wed Jan 02, 2019 5:45 pm

So there will be no issue with both of them utilizing the MISO/MOSI at separate points throughout the initialization of the impact sensor thread?

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Re: Feather accelerometer, RF transmitter, data logging proj

by adafruit_support_bill on Wed Jan 02, 2019 6:16 pm

That is what the CS pin is for. Each SPI device needs a different CS pin. You need to specify that when you initialize the device in your code. Then the libraries will assert the CS pin for the device they are communicating with. This is explained in the link I posted earlier: http://www.circuitbasics.com/basics-of- ... n-protocol

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Re: Feather accelerometer, RF transmitter, data logging proj

by wahleworld on Wed Jan 02, 2019 7:46 pm

Thank You.

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Re: Feather accelerometer, RF transmitter, data logging proj

by wahleworld on Fri Jan 04, 2019 3:47 pm

I'm currently reviewing the pinout for the feather M0 and only see one CS pin, and it's in use by the RFM.. Am I reading the layout correctly? Is there only one CS pin per feather?

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Please be positive and constructive with your questions and comments.