# Test for nrf24l01p lowlevel functions

## About

This is a small test application to see how the lowlevel-driver functions of
the proprietary nrf24l01p-transceiver work. These functions consist of general
SPI and GPIO commands, which abstract the driver-functions from the used board.

## Predefined pin mapping

Please compare the `tests/driver_nrf24l01p_lowlevel/Makefile` for predefined
pin-mappings on different boards. (In addition, you also need to connect to 3V
and GND)

## Usage

You should be presented with the RIOT shell, providing you with commands to
initialize the transceiver (command: `it`), sending one packet (command:
`send`) or read out and print all registers of the transceiver as binary values
(command: `prgs`).

### Procedure

 * take two boards and connect a transceiver to each
   (it should be also possible to use one board with different SPI-ports)
 * depending on your board, you'll maybe also need to connect a UART/tty converter
 * build and flash the test-program to each
 * open a terminal (e.g. pyterm) for each
 * if possible, reset the board by using the reset-button. You'll see "_Welcome to RIOT_" etc.
 * type `help` to see the description of the commands
 * initialize both with `it`
 * with one board, send a packet by typing `send`
 * in the next step you can also use `send` to send data in the other direction
 * now you can use send on both boards/transceivers to send messages between them


## Expected Results

After you did all steps described above, you should see that a 32 Byte sequence
(numbers from 32...1) has been transferred from one device to the other. This
sequence is printed out from the receiver after the receive interrupt occurred
and the receive-procedure has been made.

After initialization (`it`) you should see the following output:

```
 > it

Init Transceiver

Registering nrf24l01p_rx_handler thread...
################## Print Registers ###################
REG_CONFIG:
0x0 returned: 00111111

REG_EN_AA:
0x1 returned: 00000001

REG_EN_RXADDR:
0x2 returned: 00000011

REG_SETUP_AW:
0x3 returned: 00000011

REG_SETUP_RETR:
0x4 returned: 00101111

REG_RF_CH:
0x5 returned: 00000101

REG_RF_SETUP:
0x6 returned: 00100111

REG_STATUS:
0x7 returned: 00001110

REG_OBSERVE_TX:
0x8 returned: 00000000

REG_RPD:
0x9 returned: 00000000

REG_RX_ADDR_P0:
0xa returned: e7 e7 e7 e7 e7

REG_TX_ADDR:
0x10 returned: e7 e7 e7 e7 e7

REG_RX_PW_P0:
0x11 returned: 00100000

REG_FIFO_STATUS:
0x17 returned: 00010001

REG_DYNPD:
0x1c returned: 00000000

REG_FEATURE:
0x1d returned: 00000000

```

After the data has been sent (`send`), you should see the following output on the receiver terminal:
```
In HW cb
nrf24l01p_rx_handler got a message: Received packet.
32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

```