File content as of revision 2:ee9416954280:

/** \file
 * \brief
 *
 * \author Per Söderstam © 2011
 */

#include "nRF2401A.h"

const int   Ts = 1;         /**< Setup time from data to rising clock edge on write (accualy 500 ns). */
const int   Th = 1;         /**< Hold time from rising clock to data toggle/falling clock (accualy 500 ns). */
const int   Tcs2data = 5;   /**< Min delay from CS assert to data, in us. */
const int   Tce2data = 5;   /**< Min delay from CE assert to data, in us. */
const int   Td = 1;         /**< Minimum delay between edges (actually 50 ns). */
const int   Tpd2cfgm = 3;   /**< Minimum delay from power up of tranciever to configuration. */
const int   Tsby2txSB = 195;    /**< Minimum delay from tx initation to air, in us. */
const int   Thmin = 5;          /**< */
const int   Tclk2data = 1;      /**< */

nRF2401A::nRF2401A(PinName ce,
                   PinName cs,
                   PinName dr1,
                   PinName clk1,
                   PinName data)
        : _ce(DigitalOut(ce)),
        _cs(DigitalOut(cs)),
        _dr1(DigitalIn(dr1)),
        _clk1(DigitalOut(clk1)),
        _data(DigitalInOut(data)),
        _state(nRF2401A::UNDEF),
        _rx_handler((nRF2401A_rx_handler_t) 0),
        _rx_handler_arg((void *) 0),
        _dr1_isr(InterruptIn(dr1)) {

    // init member variables
    _data.output();
    // setup...
    _ctrl_packet = (uint8_t *) &_ctrl_packet_buf;
    _dr1_isr.rise(this, &nRF2401A::dataReadyHandler);
    // ...tranciever in standby...
    _ce = 0;
    _cs = 0;
    // ...and clear receive buffer
    for (int i = 0; i < 16; i++)
        _data_buf[i] = 0x0;
    // ...set imutable control fields...
    _ctrl_packet_buf.enable_dual_channel_mode = 0x0;    // single channel receive
    _ctrl_packet_buf.communication_mode = 0x1;          // ShockBurst mode
    _ctrl_packet_buf.xo_frequency = 0x3;                // 16 MHz crystal
    _ctrl_packet_buf.rf_power = 0x3;                    // 0 dBm (1 mW) output power
    // ...start in RX mode
    _ctrl_packet_buf.txr_switch = nRF2401A::RX_MODE;
    // assure minimum wake up time while assuming tranciever powers up with uP
    wait_ms(Tpd2cfgm);

    return;
}

void nRF2401A::printControlPacket(Serial& port)
{
    for(int i = 0; i < sizeof(_ctrl_packet_buf); i++)
        port.printf("%02x ", _ctrl_packet[i]);
    port.printf("\n\r");
    return;
}

void nRF2401A::printDataPacket(Serial& port)
{
    for(int i = 0; i < sizeof(_data_buf); i++)
        port.printf("%02x ", _data_buf[i]);
    port.printf("\r");
    return;
}

nRF2401A& nRF2401A::attachRXHandler(nRF2401A_rx_handler_t handler, void *arg) {

    _rx_handler = handler;
    _rx_handler_arg = arg;

    return *this;
}

nRF2401A& nRF2401A::sendMsg(nRF2401A::address_t addr, uint8_t addr_len, uint8_t *msg_buf, uint8_t msg_len) {

    // point to start of address byte in address
    uint8_t *aligned_addr = &addr[sizeof(address_t) - (addr_len / 8)];
    // wait for tx completion
    int Toa = (_ctrl_packet_buf.rf_data_rate == nRF2401A::BIT_RATE_1MBITS ? 1 : 4) * (addr_len + msg_len + 1 + 16);

    switch (_state) {
        case nRF2401A::RX:
            // switch to transmit
            _ce = 0;
            _cs = 0;
            wait_us(Td);
            // assert CS/CE and wait Tcs2data
            _ce = 0;
            _cs = 1;
            wait_us(Tcs2data);
            // push out the bits
            _data = nRF2401A::TX_MODE;
            wait_us(Ts);
            _clk1 = 1;
            wait_us(Th);
            _clk1 = 0;
            // wait Td
            wait_us(Td);
            // deassert CS/CE and done...
            _cs = 0;
            _ce = 0;

            // zero control and data lines
            _clk1 = 0;
            _data = 0;
            // wait Td
            wait_us(Td);
            // assert CE and wait Tcs2data
            _ce = 1;
            wait_us(Tce2data);
            // push out the address bits
            for (int i = 0; i < addr_len; i++) {
                _data = ((0x80 >> (i % 8)) & aligned_addr[i / 8]) ? 0x1 : 0x0;
                wait_us(Ts);
                _clk1 = 1;
                wait_us(Th);
                _clk1 = 0;
            }
            // push out the message bits
            for (int i = 0; i < msg_len; i++) {
                _data = ((0x80 >> (i % 8)) & msg_buf[i / 8]) ? 0x1 : 0x0;
                wait_us(Ts);
                _clk1 = 1;
                wait_us(Th);
                _clk1 = 0;
            }
            // reset data
            _data = 0;
            // deassert CE will initiate transmission
            _ce = 0;
            wait_us(Tsby2txSB + Toa);

            // switch back to receive
            wait_us(Td);
            // assert CS/CE and wait Tcs2data
            _cs = 1;
            wait_us(Tcs2data);
            // push out the bits
            _data = nRF2401A::RX_MODE;
            wait_us(Ts);
            _clk1 = 1;
            wait_us(Th);
            _clk1 = 0;
            // wait Td
            wait_us(Td);
            _data = 0;
            // deassert CS/CE and done...
            _cs = 0;
            // wait Td to avoid simultaineous control high
            wait_us(Td);
            _ce = 1;
            // done
            break;
        case nRF2401A::STANDBY:
        case nRF2401A::TX:
        case nRF2401A::UNDEF:
        default:
            // can only send in RX mode
            break;
    }

    return *this;
}

void nRF2401A::pushCtrl(uint8_t *buf, uint8_t n_bits, bool is_ctrl) {

    DigitalOut  &ctrl_pin = is_ctrl ? _cs : _ce;

    // set data to output
    _data.output();
    // zero control and data lines
    _cs = 0;
    _ce = 0;
    _clk1 = 0;
    _data = 0;
    // wait Td
    wait_us(Td);
    // assert CS/CE and wait Tcs2data
    ctrl_pin = 1;
    wait_us(Tcs2data);
    // push out the bits
    for (int i = 0; i < n_bits; i++) {
        _data = ((0x80 >> (i % 8)) & buf[i / 8]) ? 0x1 : 0x0;
        wait_us(Ts);
        _clk1 = 1;
        wait_us(Th);
        _clk1 = 0;
    }
    _data = 0;
    // wait Td
    wait_us(Td);
    // deassert CS/CE and done...
    ctrl_pin = 0;

    return;
}

int nRF2401A::pull(uint8_t *buf) {
    int n = 0;
    
    // read from data pin
    _data.input();
    // init signals, go to standby
    _ce = 1;
    _cs = 0;
    _clk1 = 0;
    // ensure time from DR
    wait_us(Td);
    
    while (_dr1 == 1) {
        _clk1 = 1;
        wait_us(Thmin);
        if(_data.read())
            buf[n / 8] |= (0x80 >> (n % 8));
        else
            buf[n / 8] &= ~(0x80 >> (n % 8));
        n++;
        _clk1 = 0;
        wait_us(Thmin);
    }
    // return to active
    _ce = 1;
    // reset data pin direction
    _data.output();
    
    return n;
}

void nRF2401A::activate(bool active) {
    switch (_state) {
        case nRF2401A::RX:
            if (!active) {
                _state = nRF2401A::STANDBY;
                _ce = 0;
                _cs = 0;
            }
            break;
        case nRF2401A::STANDBY:
            if (active) {
                _state = nRF2401A::RX;
                _ce = 1;
                _cs = 0;
            }
            break;
        case nRF2401A::TX:
        case nRF2401A::UNDEF:
        default:
            break;
    }

    return;
}

void nRF2401A::dataReadyHandler(void) {
    switch (_state) {
        case nRF2401A::RX:
            pull(_data_buf);
            if (_rx_handler != (nRF2401A_rx_handler_t) 0)
                _rx_handler(_rx_handler_arg);
            break;
        default:
            // todo: error msg
            break;
    }
    return;
}

nRF2401A& nRF2401A::flushControlPacket() {
    switch (_state) {
        case nRF2401A::UNDEF:
        case nRF2401A::RX:
            pushCtrl(_ctrl_packet, 15 << 3 );
            _state = nRF2401A::RX;
            _ce = 1;
            _cs = 0;
            break;
        case nRF2401A::STANDBY:
            pushCtrl(_ctrl_packet, 15 << 3 );
            _state = nRF2401A::STANDBY;
            _ce = 0;
            _cs = 0;
            break;
        case nRF2401A::TX:
        default:
            _ce = 0;
            _cs = 0;
    }

    return *this;
}