Andrew Lindsay
RFM12B radio module driver library
Diff: RF12B.cpp
- Revision:
- 0:e724d8251cdc
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/RF12B.cpp Sat Mar 31 07:11:16 2012 +0000
@@ -0,0 +1,303 @@
+/* RF12B Library. Based on work done by JeeLabs.org ported to mbed by SK Pang.
+http://jeelabs.net/projects/cafe/wiki/RF12
+
+http://opensource.org/licenses/mit-license.php
+
+Jan 2012 skpang.co.uk
+
+Modified by Andrew Lindsay (andrew [at] thiseldo [dot] co [dot] uk)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+#include "RF12B.h"
+
+DigitalOut led4(LED4, "led4");
+
+// RF12 command codes
+#define RF_RECEIVER_ON 0x82DD
+#define RF_XMITTER_ON 0x823D
+#define RF_IDLE_MODE 0x820D
+#define RF_SLEEP_MODE 0x8205
+#define RF_WAKEUP_MODE 0x8207
+#define RF_TXREG_WRITE 0xB800
+#define RF_RX_FIFO_READ 0xB000
+#define RF_WAKEUP_TIMER 0xE000
+
+// RF12 status bits
+#define RF_LBD_BIT 0x0400
+#define RF_RSSI_BIT 0x0100
+
+// bits in the node id configuration byte
+#define NODE_BAND 0xC0 // frequency band
+#define NODE_ACKANY 0x20 // ack on broadcast packets if set
+#define NODE_ID 0x1F // id of this node, as A..Z or 1..31
+
+// transceiver states, these determine what to do with each interrupt
+enum {
+ TXCRC1, TXCRC2, TXTAIL, TXDONE, TXIDLE,
+ TXRECV,
+ TXPRE1, TXPRE2, TXPRE3, TXSYN1, TXSYN2,
+};
+
+RF12B::RF12B(PinName _SDI,
+ PinName _SDO,
+ PinName _SCK,
+ PinName _NCS,
+ PinName _NIRQ):spi(_SDI, _SDO, _SCK),
+ NCS(_NCS), NIRQ(_NIRQ), NIRQ_in(_NIRQ) {
+
+ /* SPI frequency, 8 bit word length, polarity and phase */
+ spi.format(8,0);
+ spi.frequency(2000000);
+
+ /* Set ~CS high */
+ NCS = 1;
+
+ /* Setup interrupt to happen on falling edge of NIRQ */
+ NIRQ.fall(this, &RF12B::rxISR);
+}
+
+
+/**********************************************************************
+ * PRIVATE FUNCTIONS
+ *********************************************************************/
+
+/* Initialises the RF12B module */
+void RF12B::init(uint8_t id, uint8_t band, uint8_t g) {
+
+ nodeid = id;
+ group = g;
+ rf12_grp = g;
+
+ writeCmd(0x0000); // intitial SPI transfer added to avoid power-up problem
+ writeCmd(RF_SLEEP_MODE); // DC (disable clk pin), enable lbd
+
+ // wait until RFM12B is out of power-up reset, this takes several *seconds*
+ writeCmd(RF_TXREG_WRITE); // in case we're still in OOK mode
+
+ while (NIRQ == 0) writeCmd(0x0000);
+
+ // TODO: Have band specific parameters to optimise settings
+
+ writeCmd(0x80C7 | (band << 4)); // EL (ena TX), EF (ena RX FIFO), 12.0pF
+ writeCmd(0xA640); // 868MHz
+ writeCmd(0xC606); // approx 49.2 Kbps, i.e. 10000/29/(1+6) Kbps
+ writeCmd(0x94A2); // VDI,FAST,134kHz,0dBm,-91dBm
+ writeCmd(0xC2AC); // AL,!ml,DIG,DQD4
+ if (group != 0) {
+ writeCmd(0xCA83); // FIFO8,2-SYNC,!ff,DR
+ writeCmd(0xCE00 | group); // SYNC=2DXX
+ } else {
+ writeCmd(0xCA8B); // FIFO8,1-SYNC,!ff,DR
+ writeCmd(0xCE2D); // SYNC=2D
+ }
+
+ writeCmd(0xC483); // @PWR,NO RSTRIC,!st,!fi,OE,EN
+ writeCmd(0x9850); // !mp,90kHz,MAX OUT
+ writeCmd(0xCC77); // OB1, OB0, LPX, ddy, DDIT, BW0
+ writeCmd(0xE000); // NOT USE
+ writeCmd(0xC800); // NOT USE
+ writeCmd(0xC049); // 1.66MHz,3.1V
+
+ rxstate = TXIDLE;
+
+}
+
+int RF12B::available( void ) {
+
+ return (rf12_recvDone() && (check_crc() == 0) && length() < 66) ? length() : 0;
+}
+
+/* Write a command to the RF Module */
+int RF12B::writeCmd(int cmd) {
+ NCS = 0;
+ int recv = spi.write(cmd >>8);
+ recv = spi.write(cmd);
+ NCS = 1;
+ return recv;
+}
+
+/* Sends a byte of data across RF */
+void RF12B::send(uint8_t data) {
+ while (NIRQ);
+ writeCmd(0xB800 + data);
+}
+
+
+/* Interrupt routine for data reception and Txing */
+void RF12B::rxISR() {
+ led4 = 1;
+ // a transfer of 2x 16 bits @ 2 MHz over SPI takes 2x 8 us inside this ISR
+ writeCmd(0x0000);
+
+ if (rxstate == TXRECV) {
+ uint8_t in = rf12_xfer(RF_RX_FIFO_READ);
+
+ if (rxfill == 0 && group != 0)
+ rf12_buf[rxfill++] = group;
+
+ rf12_buf[rxfill++] = in;
+ rf12_crc = _crc16_update(rf12_crc, in);
+
+ if (rxfill >= rf12_len + 5 || rxfill >= RF_MAX)
+ rf12_xfer(RF_IDLE_MODE);
+ } else {
+ uint8_t out;
+
+ if (rxstate < 0) {
+ uint8_t pos = 3 + rf12_len + rxstate++;
+ out = rf12_buf[pos];
+ rf12_crc = _crc16_update(rf12_crc, out);
+ } else {
+ switch (rxstate++) {
+ case TXSYN1:
+ out = 0x2D;
+ break;
+ case TXSYN2:
+ out = rf12_grp;
+ rxstate = - (2 + rf12_len);
+ break;
+ case TXCRC1:
+ out = rf12_crc;
+ break;
+ case TXCRC2:
+ out = rf12_crc >> 8;
+ break;
+ case TXDONE:
+ rf12_xfer(RF_IDLE_MODE); // fall through
+ default:
+ out = 0xAA;
+ }
+ }
+ rf12_xfer(RF_TXREG_WRITE + out);
+ }
+ led4 = 0;
+}
+
+
+void RF12B::rf12_sendStart (uint8_t hdr, const void* ptr, uint8_t len) {
+ rf12_len = len;
+ memcpy((void*) rf12_data, ptr, len);
+ rf12_sendStart(hdr);
+}
+
+//void RF12B::rf12_sendStart2 (uint8_t hdr) {
+void RF12B::rf12_sendStart (uint8_t hdr) {
+ rf12_hdr = hdr & RF12_HDR_DST ? hdr :
+ (hdr & ~RF12_HDR_MASK) + (nodeid & NODE_ID);
+
+ /*
+ if (crypter != 0)
+ crypter(1);
+ */
+ rf12_crc = ~0;
+
+ rf12_crc = _crc16_update(rf12_crc, rf12_grp);
+ rxstate = TXPRE1;
+
+ rf12_xfer(RF_XMITTER_ON); // bytes will be fed via interrupts
+}
+
+
+uint16_t RF12B::rf12_xfer (uint16_t cmd) {
+ NCS = 0;
+ uint16_t reply = rf12_byte(cmd >> 8) << 8;
+ reply |= rf12_byte(cmd);
+ NCS = 1;
+ return reply;
+}
+
+void RF12B::rf12_recvStart (void) {
+ rxfill = rf12_len = 0;
+ rf12_crc = ~0;
+
+ if (group != 0)
+ rf12_crc = _crc16_update(~0, group);
+
+ rxstate = TXRECV;
+ rf12_xfer(RF_RECEIVER_ON);
+}
+
+uint16_t RF12B::check_crc(void) {
+ return rf12_crc;
+}
+
+uint8_t RF12B::length(void) {
+ return rf12_len;
+}
+
+uint8_t* RF12B::get_data(void) {
+ return (uint8_t*)rf12_buf;
+}
+
+uint8_t* RF12B::get_payload(void) {
+ return (uint8_t*)rf12_data;
+}
+
+uint8_t RF12B::rf12_recvDone (void) {
+
+ if (rxstate == TXRECV && (rxfill >= rf12_len + 5 || rxfill >= RF_MAX)) {
+ rxstate = TXIDLE;
+
+ if (rf12_len > RF12_MAXDATA)
+ rf12_crc = 1; // force bad crc if packet length is invalid
+ if (!(rf12_hdr & RF12_HDR_DST) || (nodeid & NODE_ID) == 31 ||
+ (rf12_hdr & RF12_HDR_MASK) == (nodeid & NODE_ID)) {
+ /*
+ printf("RX Len: %d ", rf12_len+6);
+ for (int i=0; i<rf12_len+6; i++) {
+ printf("%02X ",rf12_buf[i]);
+ }
+ printf(" crc:%x\n",rf12_crc);
+ */
+ /*
+ if (rf12_crc == 0 && crypter != 0)
+ crypter(0);
+ else
+ rf12_seq = -1;
+ */
+ return 1; // it's a broadcast packet or it's addressed to this node
+
+ }
+ }
+ if (rxstate == TXIDLE)
+ rf12_recvStart();
+ return 0;
+}
+
+uint8_t RF12B::rf12_byte(uint8_t out) {
+// unsigned char recv = spi.write(out);
+// return recv;
+ return spi.write(out);
+}
+
+uint16_t RF12B::_crc16_update(uint16_t crc, uint8_t data) {
+ int i;
+
+ crc ^= data;
+ for (i = 0; i < 8; ++i) {
+ if (crc & 1)
+ crc = (crc >> 1) ^ 0xA001;
+ else
+ crc = (crc >> 1);
+ }
+
+ return crc;
+}