Range issue in Remote control using CC2500

Hi,

You should easily get much more than 50m range. However, we need some more information than what you have given us in order to help you. What kind of debugging have you done? Have you measured the output power? What reg settings are you using?

-P

vijay,

50 mts is easily achievable using the CC2500.

If you could provide your configuration register settings and the Power output, that will be really helpful.

There might be a mismatch in your RF antenna network too which might be one of the reasons of this low range.

You can also check out Anaren's A2500R24 design which are based on CC2500 and are FCC and Etsi certified.

Link : http://www.anaren.com/content/File/AIR/A2500R24AGR.cfm

Hope this helps.

- The Air team @ Anaren.

Please check out our Air Modules at http://www.anaren.com/content/File/AIR/AIRoverview.cfm

Anaren is a third party Developer Network Member for Low Power RF and MCUs.

Dears

  Sorry for the delay reply , i was delayed on site testing,

1.Kind of debugging,

           We just check using UASRT output , for some datas which are transmitted by the remote unit.

While testing we got junk values when the range is more than 12-15 meters.This results in error and null ouputs on site.

Let me know how we can debug.

2. We measured the output power using spectro meter , which shows 19dBm

3. The below are the register settings we used,

  Write2CC2500(CC2500_FSCTRL1,  0x08); // Freq synthesizer control.
  Write2CC2500(CC2500_FSCTRL0,  0x00); // Freq synthesizer control.

  Write2CC2500(CC2500_FREQ2,    0x5C); // Freq control word, high byte  0x5A  0x58
  Write2CC2500(CC2500_FREQ1,    0x58); // Freq control word, mid byte.  0x1C  0xE3
  Write2CC2500(CC2500_FREQ0,    0x9D); // Freq control word, low byte.  0x71  0x8E

  Write2CC2500(CC2500_MDMCFG4,  0x86); // Modem configuration.0x0e//0x08
  Write2CC2500(CC2500_MDMCFG3,  0x83); // Modem configuration.0x2F
  Write2CC2500(CC2500_MDMCFG2,  0x03); // Modem configuration.0x7b
  Write2CC2500(CC2500_MDMCFG1,  0x22); // Modem configuration.0x42
  Write2CC2500(CC2500_MDMCFG0,  0xF8); // Modem configuration.
 
  Write2CC2500(CC2500_CHANNR,   0x03); // Channel number.
  Write2CC2500(CC2500_DEVIATN,  0x44); // Modem dev (when FSK mod en)
  Write2CC2500(CC2500_FREND1,   0x56); // Front end RX configuration.
  Write2CC2500(CC2500_FREND0,   0x10); // Front end TX configuration.

  Write2CC2500(CC2500_MCSM1 ,   0x3e); //MainRadio Cntrl State Machine
  Write2CC2500(CC2500_MCSM0 ,   0x18); //MainRadio Cntrl State Machine
  Write2CC2500(CC2500_FOCCFG,   0x16); // Freq Offset Compens. Config
  Write2CC2500(CC2500_BSCFG,    0x6c); //  Bit synchronization config.
   
  Write2CC2500(CC2500_AGCCTRL2, 0x03); // AGC control.
  Write2CC2500(CC2500_AGCCTRL1, 0x40); // AGC control.
  Write2CC2500(CC2500_AGCCTRL0, 0x91); // AGC control.

  Write2CC2500(CC2500_FSCAL3,  0xA9); // Frequency synthesizer cal.
  Write2CC2500(CC2500_FSCAL2,   0x0A); // Frequency synthesizer cal.
  Write2CC2500(CC2500_FSCAL1,   0x00); // Frequency synthesizer cal.
  Write2CC2500(CC2500_FSCAL0,   0x11); // Frequency synthesizer cal.

  Write2CC2500(CC2500_SYNC1,   0x72);
  Write2CC2500(CC2500_SYNC0,   0x47);

  Write2CC2500(CC2500_FSTEST,   0x59); // Frequency synthesizer cal.
  Write2CC2500(CC2500_TEST2,    0x88); // Various test settings.
  Write2CC2500(CC2500_TEST1,    0x31); // Various test settings.
  Write2CC2500(CC2500_TEST0,    0x0B);  // Various test settings.

  Write2CC2500(CC2500_IOCFG2,   0x29);  // GDO2 output pin config.
  Write2CC2500(CC2500_IOCFG0,   0x06);  // GDO0 output pin config.
  Write2CC2500(CC2500_PKTCTRL1, 0x00);  // Packet automation control.
  Write2CC2500(CC2500_PKTCTRL0, 0x40);  // Packet automation control.//0x40
  Write2CC2500(CC2500_PKTLEN, 0x05);  // Packet length.//0x0A
  Write2CC2500(CC2500_PATABLE, 0xFE);  // Packet length.//0x0A

thank you.

Vijayakumar,

Your registers appear okay to me.  You're running at 2.4 kbaud, 2-FSK at a base frequency of 2401MHz.  The only differences from the SmartRF Studio settings appear to be:

-MCSM2 is not specified.  Probably okay, since the default value is the recommended value.

-Sync byte is somewhat different from the recommended 0xD391.  I don't think that should be a problem, though

-The radio isn't using the built-in CRC function.  OK. 

-The radio is set to go back immediately to RX or TX after it receives or transmits, respectively, a packet.  This means that the automatic calibration won't be performed, since the radio never transitions from IDLE to RX or TX.  That should be okay unless the temperature or power supply voltage changes significantly.

-Fixed packet length mode (packet length=5).  This is okay.

Do you know whether the RSSI is about what's expected on the receiving unit? 

Hi,

Have you measured your sensitivity? Here is a link to a appnote descrbing how to measure the sensitivity:

http://focus.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=swra097

Per H