nRF key

Interface for Nordic nRF24L01 wireless modules.

Project structure

In this repository you can find:

nRF-key
 |__ schematics --> KiCAD schematic
 |__ code       --> source code for ATtiny2313 microcontroller

BOM

Designator	Description	MPN
C2 C7 C8 C10	capacitor 100n 0805	0805F104M500NT
C9	capacitor tantalum 10u	TAJA106K016RNJ
C5 C6	capacitor 22p 0805	0805N220J500CT
D1 D2 D3	red led 0805	QBLP631-R
R1 R5	resistor 10k 0805	RC0805JR-0710KL
R2 R3 R4	Resistor 330 0805	0805W8J0331T5E
U2	microcontroller ATtiny2313	ATTINY2313A-SU
U1	usb ttl uart ch340c	CH340C
U3	LDO voltage regulator 3v3	MCP1700T-3302E/TT
Y1	crystal 8M	1C208000BC0R

Code features

Communication with nRF key is via 9600baud 8N1 serial port. Data received from another module is printed. Data to send is packaged in a 32byte maximum structure and must be followed by CR. Bytes over 32 (except for CR) will be ignored. This is not a transparent bridge, but can be easily implemented.

nRF24L01 registers (i.e. tx/rx addresses) can be reprogrammed pressing programming button (i.e. holding low BTN/PD4 line) while inserting key. Programming mode is selected (both TX_LED and RX_LED will turn on), next 32byte will be stored in settings EEPROM. Data is structured as following:

Byte n.	Function	nRF reg.
0	Configure register	0
1	Enable automatic answer function	1
2	Enable receive address	2
3	Setup address width	3
4	Automatic retransmission	4
5	Set channel frequency	5
6	Set transmission rate, LNA gain, transmit power	6
7÷11	RX address for data channel 0	10
12÷16	RX address for data channel 1	11
17	RX address for data channel 2	12
18	RX address for data channel 3	13
19	RX address for data channel 4	14
20	RX address for data channel 5	15
21÷25	TX address	16
26	RX data for channel 0	17
27	RX data for channel 1	18
28	RX data for channel 2	19
29	RX data for channel 3	20
30	RX data for channel 4	21
31	RX data for channel 5	22

How To

1. Make the PCB and solde it (I have a protoboard version too);
2. Obtain an AVR programmer (usbasp or Arduino as ISP)
3. Compile the code:

• install gcc-avr avr-libc avrdude;
• move in code directory;
• type make;
• check in Makefile if the programmer is correct;
• type make eeprom then make flash.

Authors

• Giulio Fieramosca - giuliof

License

This project is released under the MIT License - see the LICENSE.md file for details