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RH_NRF51.cpp
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RH_NRF51.cpp
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// NRF51.cpp
//
// Per: nRF51_Series_Reference_manual v3.0.pdf
// Copyright (C) 2012 Mike McCauley
// $Id: RH_NRF51.cpp,v 1.4 2017/02/01 21:46:02 mikem Exp $
// Set by Arduino IDE and RadioHead.h when compiling for nRF51 or nRF52 chips:
#include <RH_NRF51.h>
#if RH_PLATFORM==RH_PLATFORM_NRF51
RH_NRF51::RH_NRF51()
: _rxBufValid(false)
#if RH_NRF51_HAVE_ENCRYPTION
, _encrypting(false)
#endif
{
}
bool RH_NRF51::init()
{
// Enable the High Frequency clock to the system as a whole
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
NRF_CLOCK->TASKS_HFCLKSTART = 1;
/* Wait for the external oscillator to start up */
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0)
;
// Disable and reset the radio
NRF_RADIO->POWER = RADIO_POWER_POWER_Disabled;
NRF_RADIO->POWER = RADIO_POWER_POWER_Enabled;
NRF_RADIO->EVENTS_DISABLED = 0;
NRF_RADIO->TASKS_DISABLE = 1;
// Wait until we are in DISABLE state
while (NRF_RADIO->EVENTS_DISABLED == 0) {}
// Physical on-air address is set in PREFIX0 + BASE0 by setNetworkAddress
NRF_RADIO->TXADDRESS = 0x00; // Use logical address 0 (PREFIX0 + BASE0)
NRF_RADIO->RXADDRESSES = 0x01; // Enable reception on logical address 0 (PREFIX0 + BASE0)
// Configure the CRC
NRF_RADIO->CRCCNF = (RADIO_CRCCNF_LEN_Two << RADIO_CRCCNF_LEN_Pos); // Number of checksum bits
NRF_RADIO->CRCINIT = 0xFFFFUL; // Initial value
NRF_RADIO->CRCPOLY = 0x11021UL; // CRC poly: x^16+x^12^x^5+1
// These shorts will make the radio transition from Ready to Start to Disable automatically
// for both TX and RX, which makes for much shorter on-air times
NRF_RADIO->SHORTS = (RADIO_SHORTS_READY_START_Enabled << RADIO_SHORTS_READY_START_Pos)
| (RADIO_SHORTS_END_DISABLE_Enabled << RADIO_SHORTS_END_DISABLE_Pos);
NRF_RADIO->PCNF0 = (8 << RADIO_PCNF0_LFLEN_Pos) // Payload size length in bits
| (1 << RADIO_PCNF0_S0LEN_Pos) // S0 is 1 octet
| (8 << RADIO_PCNF0_S1LEN_Pos); // S1 is 1 octet
// Make sure we are powered down
setModeIdle();
// Set a default network address
uint8_t default_network_address[] = {0xE7, 0xE7, 0xE7, 0xE7, 0xE7};
setNetworkAddress(default_network_address, sizeof(default_network_address));
setChannel(2); // The default, in case it was set by another app without powering down
setRF(RH_NRF51::DataRate2Mbps, RH_NRF51::TransmitPower0dBm);
setEncryptionKey(NULL);
return true;
}
bool RH_NRF51::setChannel(uint8_t channel)
{
NRF_RADIO->FREQUENCY = ((channel << RADIO_FREQUENCY_FREQUENCY_Pos) & RADIO_FREQUENCY_FREQUENCY_Msk);
return true;
}
bool RH_NRF51::setNetworkAddress(uint8_t* address, uint8_t len)
{
if (len < 3 || len > 5)
return false;
// First byte is the prefix, remainder are base
NRF_RADIO->PREFIX0 = ((address[0] << RADIO_PREFIX0_AP0_Pos) & RADIO_PREFIX0_AP0_Msk);
uint32_t base;
memcpy(&base, address+1, len-1);
NRF_RADIO->BASE0 = base;
NRF_RADIO->PCNF1 = (
(((sizeof(_buf)) << RADIO_PCNF1_MAXLEN_Pos) & RADIO_PCNF1_MAXLEN_Msk) // maximum length of payload
| (((0UL) << RADIO_PCNF1_STATLEN_Pos) & RADIO_PCNF1_STATLEN_Msk) // expand the payload with 0 bytes
| (((len-1) << RADIO_PCNF1_BALEN_Pos) & RADIO_PCNF1_BALEN_Msk)); // base address length in number of bytes.
return true;
}
bool RH_NRF51::setRF(DataRate data_rate, TransmitPower power)
{
uint8_t mode;
uint8_t p;
if (data_rate == DataRate2Mbps)
mode = RADIO_MODE_MODE_Nrf_2Mbit;
else if (data_rate == DataRate1Mbps)
mode = RADIO_MODE_MODE_Nrf_1Mbit;
else if (data_rate == DataRate250kbps)
mode = RADIO_MODE_MODE_Nrf_250Kbit;
else
return false;// Invalid
if (power == TransmitPower4dBm)
p = RADIO_TXPOWER_TXPOWER_Pos4dBm;
else if (power == TransmitPower0dBm)
p = RADIO_TXPOWER_TXPOWER_0dBm;
else if (power == TransmitPowerm4dBm)
p = RADIO_TXPOWER_TXPOWER_Neg4dBm;
else if (power == TransmitPowerm8dBm)
p = RADIO_TXPOWER_TXPOWER_Neg8dBm;
else if (power == TransmitPowerm12dBm)
p = RADIO_TXPOWER_TXPOWER_Neg12dBm;
else if (power == TransmitPowerm16dBm)
p = RADIO_TXPOWER_TXPOWER_Neg16dBm;
else if (power == TransmitPowerm20dBm)
p = RADIO_TXPOWER_TXPOWER_Neg20dBm;
else if (power == TransmitPowerm30dBm)
p = RADIO_TXPOWER_TXPOWER_Neg30dBm;
else
return false; // Invalid
NRF_RADIO->TXPOWER = ((p << RADIO_TXPOWER_TXPOWER_Pos) & RADIO_TXPOWER_TXPOWER_Msk);
NRF_RADIO->MODE = ((mode << RADIO_MODE_MODE_Pos) & RADIO_MODE_MODE_Msk);
return true;
}
void RH_NRF51::setModeIdle()
{
if (_mode != RHModeIdle)
{
NRF_RADIO->EVENTS_DISABLED = 0U;
NRF_RADIO->TASKS_DISABLE = 1;
while (NRF_RADIO->EVENTS_DISABLED == 0U)
; // wait for the radio to be disabled
NRF_RADIO->EVENTS_END = 0U;
_mode = RHModeIdle;
}
}
void RH_NRF51::setModeRx()
{
if (_mode != RHModeRx)
{
setModeIdle(); // Can only start RX from DISABLE state
#if RH_NRF51_HAVE_ENCRYPTION
// Maybe set the AES CCA module for the correct encryption mode
if (_encrypting)
NRF_CCM->MODE = (CCM_MODE_MODE_Decryption << CCM_MODE_MODE_Pos); // Decrypt
NRF_CCM->MICSTATUS = 0;
#endif
// Radio will transition automatically to Disable state when a message is received
NRF_RADIO->PACKETPTR = (uint32_t)_buf;
NRF_RADIO->EVENTS_READY = 0U;
NRF_RADIO->TASKS_RXEN = 1;
NRF_RADIO->EVENTS_END = 0U; // So we can detect end of reception
_mode = RHModeRx;
}
}
void RH_NRF51::setModeTx()
{
if (_mode != RHModeTx)
{
setModeIdle(); // Can only start RX from DISABLE state
// Sigh: it seems that it takes longer to start the receiver than the transmitter for this type
// of radio, so if a message is received and an ACK or reply is sent to soon, the original transmitter
// may not see the reply. So we delay here to make sure the receiver is ready.
// Yes, I know this is very ugly
delay(1);
#if RH_NRF51_HAVE_ENCRYPTION
// Maybe set the AES CCA module for the correct encryption mode
if (_encrypting)
NRF_CCM->MODE = (CCM_MODE_MODE_Encryption << CCM_MODE_MODE_Pos); // Encrypt
#endif
// Radio will transition automatically to Disable state at the end of transmission
NRF_RADIO->PACKETPTR = (uint32_t)_buf;
NRF_RADIO->EVENTS_READY = 0U;
NRF_RADIO->TASKS_TXEN = 1;
NRF_RADIO->EVENTS_END = 0U; // So we can detect end of transmission
_mode = RHModeTx;
}
}
bool RH_NRF51::send(const uint8_t* data, uint8_t len)
{
if (len > RH_NRF51_MAX_MESSAGE_LEN)
return false;
#if RH_NRF51_HAVE_ENCRYPTION
if (_encrypting && len > RH_NRF51_MAX_ENCRYPTED_MESSAGE_LEN)
return false;
#endif
if (!waitCAD())
return false; // Check channel activity
// Set up the headers
_buf[0] = 0; // S0
_buf[1] = len + RH_NRF51_HEADER_LEN;
_buf[2] = 0; // S1
// The following octets are subject to encryption
_buf[3] = _txHeaderTo;
_buf[4] = _txHeaderFrom;
_buf[5] = _txHeaderId;
_buf[6] = _txHeaderFlags;
memcpy(_buf+RH_NRF51_HEADER_LEN, data, len);
_rxBufValid = false;
setModeTx();
// Radio will return to Disabled state after transmission is complete
_txGood++;
return true;
}
bool RH_NRF51::waitPacketSent()
{
// If we are not currently in transmit mode, there is no packet to wait for
if (_mode != RHModeTx)
return false;
// When the Disabled event occurs we know the transmission has completed
while (!NRF_RADIO->EVENTS_END)
{
YIELD;
}
setModeIdle();
return true;
}
bool RH_NRF51::isSending()
{
return (NRF_RADIO->STATE == RADIO_STATE_STATE_Tx) ? true : false;
}
bool RH_NRF51::printRegisters()
{
#ifdef RH_HAVE_SERIAL
uint16_t i;
uint32_t* p = (uint32_t*)NRF_RADIO;
for (i = 0; (p + i) < (uint32_t*) (((NRF_RADIO_Type*)NRF_RADIO) + 1); i++)
{
Serial.print("Offset: ");
Serial.print(i, DEC);
Serial.print(" ");
Serial.println(*(p+i), HEX);
}
#endif
return true;
}
// Check whether the latest received message is complete and uncorrupted
void RH_NRF51::validateRxBuf()
{
if (_buf[1] < RH_NRF51_HEADER_LEN)
return; // Too short to be a real message
// Extract the 4 headers following S0, LEN and S1
_rxHeaderTo = _buf[3];
_rxHeaderFrom = _buf[4];
_rxHeaderId = _buf[5];
_rxHeaderFlags = _buf[6];
if (_promiscuous ||
_rxHeaderTo == _thisAddress ||
_rxHeaderTo == RH_BROADCAST_ADDRESS)
{
_rxGood++;
_rxBufValid = true;
}
}
void RH_NRF51::setEncryptionKey(uint8_t* key)
{
#if RH_NRF51_HAVE_ENCRYPTION
if (key)
{
// Configure for on-the-fly encryption
// Set the key
memset(_encryption_cnf, 0, sizeof(_encryption_cnf));
memcpy(_encryption_cnf, key, RH_NRF51_ENCRYPTION_KEY_LENGTH);
// AES configuration data area
// Note that the IV (Nonce) is not set, defaults to 0s
NRF_CCM->CNFPTR = (uint32_t)_encryption_cnf;
// Set AES CCM input and putput buffers
// Make sure the _buf is encrypted and put back into _buf
NRF_CCM->INPTR = (uint32_t)_buf;
NRF_CCM->OUTPTR = (uint32_t)_buf;
// Also need to set SCRATCHPTR temp buffer os size 16+MAXPACKETSIZE in RAM
// FIXME: shared buffers if several radios
NRF_CCM->SCRATCHPTR = (uint32_t)_scratch;
// SHORT from RADIO READY to AESCCM KSGEN using PPI predefined channel 24
// Also RADIO ADDRESS to AESCCM CRYPT using PPI predefined channel 25
NRF_PPI->CHENSET = (PPI_CHENSET_CH24_Enabled << PPI_CHENSET_CH24_Pos)
| (PPI_CHENSET_CH25_Enabled << PPI_CHENSET_CH25_Pos)
;
// SHORT from AESCCM ENDKSGEN to AESCCM CRYPT
NRF_CCM->SHORTS = (CCM_SHORTS_ENDKSGEN_CRYPT_Enabled << CCM_SHORTS_ENDKSGEN_CRYPT_Pos);
// Enable the CCM module
NRF_CCM->ENABLE = (CCM_ENABLE_ENABLE_Enabled << CCM_ENABLE_ENABLE_Pos);
_encrypting = true;
}
else
{
// Disable the CCM module
NRF_CCM->ENABLE = (CCM_ENABLE_ENABLE_Disabled << CCM_ENABLE_ENABLE_Pos);
_encrypting = false;
}
#endif
}
bool RH_NRF51::available()
{
if (!_rxBufValid)
{
if (_mode == RHModeTx)
return false;
setModeRx();
if (!NRF_RADIO->EVENTS_END)
return false; // No message yet
setModeIdle();
#if RH_NRF51_HAVE_ENCRYPTION
// If encryption is enabled, the decrypted message is not available yet, and there seems
// to be no way to be sure when its ready, but a delay of 2ms is enough
if (_encrypting)
delay(2);
#endif
if (!NRF_RADIO->CRCSTATUS)
{
// Bad CRC, restart the radio
_rxBad++;
setModeRx();
return false;
}
validateRxBuf();
if (!_rxBufValid)
setModeRx(); // Try for another
}
return _rxBufValid;
}
void RH_NRF51::clearRxBuf()
{
_rxBufValid = false;
_buf[1] = 0;
}
bool RH_NRF51::recv(uint8_t* buf, uint8_t* len)
{
if (!available())
return false;
if (buf && len)
{
// Skip the 4 headers that are at the beginning of the rxBuf
// the payload length is the first octet in _buf
if (*len > _buf[1]-RH_NRF51_HEADER_LEN)
*len = _buf[1]-RH_NRF51_HEADER_LEN;
memcpy(buf, _buf+RH_NRF51_HEADER_LEN, *len);
}
clearRxBuf(); // This message accepted and cleared
return true;
}
uint8_t RH_NRF51::maxMessageLength()
{
#if RH_NRF51_HAVE_ENCRYPTION
if (_encrypting)
return RH_NRF51_MAX_ENCRYPTED_MESSAGE_LEN;
#endif
return RH_NRF51_MAX_MESSAGE_LEN;
}
float RH_NRF51::get_temperature()
{
NRF_TEMP->EVENTS_DATARDY = 0;
NRF_TEMP->TASKS_START = 1;
while (!NRF_TEMP->EVENTS_DATARDY)
;
return NRF_TEMP->TEMP * 0.25;
}
#endif // NRF51