removed previous workaround for already fixed bug in CC2420 CRC
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9508d2c4d7
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@ -26,7 +26,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: CC2420RadioPacketConverter.java,v 1.15 2010/03/09 10:37:47 nifi Exp $
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* $Id: CC2420RadioPacketConverter.java,v 1.16 2010/03/26 13:33:40 fros4943 Exp $
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*/
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package se.sics.cooja.mspmote.interfaces;
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@ -54,7 +54,7 @@ public class CC2420RadioPacketConverter {
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int pos = 0;
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byte packetData[] = packet.getPacketData();
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byte len; /* total packet minus preamble(4), synch(1) and length(1) */
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WrapperCC2420CRC cc2420CRC = new WrapperCC2420CRC();
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CCITT_CRC cc2420CRC = new CCITT_CRC();
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short contikiCRC = 0;
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/* 4 bytes preamble */
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@ -90,29 +90,29 @@ public class CC2420RadioPacketConverter {
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/* 4 byte X-MAC: not implemented */
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if (WITH_XMAC) {
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cc2420Data[pos++] = 1; /* TYPE_DATA */
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cc2420CRC.add(1);
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cc2420CRC.addBitrev(1);
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contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
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cc2420Data[pos++] = 0;
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cc2420CRC.add(0);
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cc2420CRC.addBitrev(0);
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contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
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cc2420Data[pos++] = 0; /* XXX sender: 0.0 */
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cc2420CRC.add(0);
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cc2420CRC.addBitrev(0);
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contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
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cc2420Data[pos++] = 0;
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cc2420CRC.add(0);
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cc2420CRC.addBitrev(0);
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contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
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cc2420Data[pos++] = 0; /* XXX receiver: 0.0 */
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cc2420CRC.add(0);
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cc2420CRC.addBitrev(0);
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contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
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cc2420Data[pos++] = 0;
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cc2420CRC.add(0);
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cc2420CRC.addBitrev(0);
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contikiCRC = CRCCoder.crc16Add((byte)0, contikiCRC);
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}
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/* Payload */
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for (byte b : packetData) {
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contikiCRC = CRCCoder.crc16Add(b, contikiCRC);
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cc2420CRC.add(b & 0xFF);
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cc2420CRC.addBitrev(b & 0xFF);
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}
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System.arraycopy(packetData, 0, cc2420Data, pos, packetData.length);
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pos += packetData.length;
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@ -120,28 +120,25 @@ public class CC2420RadioPacketConverter {
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/* 2 bytes checksum */
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if (WITH_CHECKSUM) {
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cc2420Data[pos++] = (byte) (contikiCRC & 0xff);
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cc2420CRC.add(contikiCRC & 0xFF);
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cc2420CRC.addBitrev(contikiCRC & 0xFF);
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cc2420Data[pos++] = (byte) ((contikiCRC >> 8) & 0xff);
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cc2420CRC.add((contikiCRC >> 8) & 0xFF);
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cc2420CRC.addBitrev((contikiCRC >> 8) & 0xFF);
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}
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/* (TODO) 3 bytes timestamp */
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if (WITH_TIMESTAMP) {
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cc2420Data[pos++] = 0;
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cc2420CRC.add(0);
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cc2420CRC.addBitrev(0);
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cc2420Data[pos++] = 0;
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cc2420CRC.add(0);
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cc2420CRC.addBitrev(0);
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cc2420Data[pos++] = 0;
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cc2420CRC.add(0);
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cc2420CRC.addBitrev(0);
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}
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/* 2 bytes footer: CC2420's CRC */
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if (WITH_FOOTER) {
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/* TODO XXX Workaround for (potential) CC2420 bug:
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* it excludes the last byte in the CRC */
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int crc = cc2420CRC.getPreviousCRC();
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cc2420Data[pos++] = (byte) ((crc >> 8) & 0xff);
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cc2420Data[pos++] = (byte) (crc & 0xff);
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cc2420Data[pos++] = (byte) cc2420CRC.getCRCHi();
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cc2420Data[pos++] = (byte) cc2420CRC.getCRCLow();
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}
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byte cc2420DataStripped[] = new byte[pos];
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@ -209,18 +206,4 @@ public class CC2420RadioPacketConverter {
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return new ConvertedRadioPacket(convertedData, originalData);
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}
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private static class WrapperCC2420CRC extends CCITT_CRC {
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int previous = 0;
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public WrapperCC2420CRC() {
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super();
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}
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public int add(int data) {
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previous = getCRC();
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return super.add(data);
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}
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public int getPreviousCRC() {
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return previous;
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}
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}
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}
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