nRF51 dongle Arduino / ATmega AVR with TWI ANT

RE: nRF51 dongle Arduino / ATmega AVR with TWI ANT

awneil — Sat, 16 Jan 2016 18:28:49 GMT

I've not used the nRF51 I2C, but the way to check is the same as for any microcontroller:

Look at the chip datasheet to see what pins can function as I2C;
Look at the dongle schematics to see if any of the available connections map to the I2C-capable pins identified above.

The radio scheme you describe should be possible, but is certainly not a beginner project. You should plan to take some time to get familiar with ANT and the Nordic systems and experiment with simple connections before attempting the mesh ...

RE: nRF51 dongle Arduino / ATmega AVR with TWI ANT

erltot — Sat, 16 Jan 2016 18:15:47 GMT

Excellent, I am just starting with the nordic chips now, but have some arduino and avr experience. Just to clarify - I am correct to assume that I can use the available GPIO pins on this dongle as twi as well then and that I can use the ant stack to communicate between my robots? Can I also use one dongle on my computer to communicate through UART to a server application? If this is somehow very complicated i'd like to know before I dig into this :-) Thank you for your replies so far.

RE: nRF51 dongle Arduino / ATmega AVR with TWI ANT

awneil — Sat, 16 Jan 2016 18:09:10 GMT

So the PCA10031, then. Yes, I would guess that the 'VDD_3.3V' would be the one to use for the pullups - you should download the schematics to check ...

RE: nRF51 dongle Arduino / ATmega AVR with TWI ANT

erltot — Sat, 16 Jan 2016 16:49:53 GMT

www.nordicsemi.com/.../nRF51-Dongle

RE: nRF51 dongle Arduino / ATmega AVR with TWI ANT

awneil — Sat, 16 Jan 2016 16:43:18 GMT

Not sure which "3.3V edge connector" you're referring to? Which "dongle", exactly, are you using?

RE: nRF51 dongle Arduino / ATmega AVR with TWI ANT

erltot — Sat, 16 Jan 2016 14:58:41 GMT

Yes, I have done something similar to connect arduino and rpi before. I need to use the 3.6-5.5V input on the nRF51 Dongle for power, can I use the 3.3V edge connector for the pull-ups?

RE: nRF51 dongle Arduino / ATmega AVR with TWI ANT

awneil — Sat, 16 Jan 2016 14:55:22 GMT

If you connect the TWI (I2C) pullups to the nRF51 3V supply, that should be OK - so long as nothing on the Arduino is pulling-up to 5V...

RE: nRF51 dongle Arduino / ATmega AVR with TWI ANT

RK — Sat, 16 Jan 2016 14:14:01 GMT

It'll destroy the chip. You can't run a GPIO pin above the Vdd level of the chip, well you can add 0.3V. The max Vdd is 3.9 so if you absolutely lived on the edge, ran the nrf at 3.9 and put the highest allowable voltage on the pin, that would be 3.9 + 0.3 = 4.2V. 5V will just leave you with a Kentucky Fried piece of silicon.

You need a level shifter if you're going to interface those things.