nrf24l01 v0.1.0

nRF24L01+ 2.4 GHz SPI transceiver core.

Application scenarios

• A short-range sensor link.
• A remote control or RC channel.
• A low-power telemetry node.

Contract

uint8_t nrf24l01_init(nrf24l01_t *radio, nrf24l01_port_t port,
                      uint8_t channel, const uint8_t address[5],
                      uint8_t payload_length);
uint8_t nrf24l01_send(nrf24l01_t *radio, const uint8_t *data, uint8_t length);
uint8_t nrf24l01_receive(nrf24l01_t *radio, uint8_t *data, uint8_t capacity,
                         uint8_t *length);

• init configures a 5-byte address, 1 Mbps, 0 dBm, CRC, and auto-ack on pipe 0.
• send writes a payload and waits for TX_DS or MAX_RT.
• receive polls RX_DR and reads one payload if present.
• Returns 1 on success or a received packet, 0 on timeout or a bus error.

Parameters

• Channel 0..125 (2400..2525 MHz).
• Payload 1..32 bytes; payload_length must match the receiver.
• Address is 5 bytes; both ends must use the same address.
• CE is driven by the adapter; SPI is mode 0.

Memory and timing

• 16 bytes; one payload buffer of up to 32 bytes.
• A send waits up to 100 ms for TX_DS; retries are configured by SETUP_RETR.

Integration

static const uint8_t address[5] = {0xE7, 0xE7, 0xE7, 0xE7, 0xE7};
nrf24l01_t radio;
nrf24l01_init(&radio, board_nrf24l01_port(), 76, address, 4);
uint8_t payload[4] = {1, 2, 3, 4};
nrf24l01_send(&radio, payload, sizeof(payload));

Adapters

• The adapter drives CSN, SCK, MOSI, MISO, and CE, and provides a 1 ms delay.
• Reference: LibDriver nrf24l01 (MIT) and the Nordic nRF24L01+ datasheet.
• This implementation is original.

When not to use

• A link that needs more than 32 bytes per packet; add a transport layer.
• A long-range or licensed band; use a different radio.

Verification

make test covers the init registers, a transmit completion, a received

payload, and a missing packet.

void *context;
void (*select)(void *context);
uint8_t (*transfer)(void *context, uint8_t value);
void (*deselect)(void *context);
void (*ce)(void *context, uint8_t level);
void (*delay_ms)(void *context, uint16_t milliseconds);

nrf24l01_port_t port;
uint8_t channel;
uint8_t payload_length;