CC2500: High data rate communications problems with 2-FSK

Sorry, I do not why the screen print do not appeared.

These are my settings:

# Address Config = No address check
# Base Frequency = 2433.000000
# CRC Autoflush = false
# CRC Enable = true
# Carrier Frequency = 2433.000000
# Channel Number = 0
# Channel Spacing = 199.951172
# Data Format = Normal mode
# Data Rate = 299.927
# Deviation = 101.562500
# Device Address = 0
# Manchester Enable = false
# Modulated = true
# Modulation Format = 2-FSK
# Preamble Count = 4
# RX Filter BW = 406.250000
# Sync Word Qualifier Mode = 30/32 sync word bits detected
# TX Power = 0
# Whitening = false
//
// Rf settings for CC2500
//
TI_CC_SPIWriteReg(TI_CCxxx0_IOCFG0,0x06);    //GDO0OUTPUT PIN CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_PKTCTRL0,0x05);  //PACKET AUTOMATION CONTROL
TI_CC_SPIWriteReg(TI_CCxxx0_FSCTRL1,0x0B);   //FREQUENCY SYNTHESIZER CONTROL
TI_CC_SPIWriteReg(TI_CCxxx0_FREQ2,0x5D);     //FREQUENCY CONTROL WORD, HIGH BYTE
TI_CC_SPIWriteReg(TI_CCxxx0_FREQ1,0x93);     //FREQUENCY CONTROL WORD, MIDDLE BYTE
TI_CC_SPIWriteReg(TI_CCxxx0_FREQ0,0xB1);     //FREQUENCY CONTROL WORD, LOW BYTE
TI_CC_SPIWriteReg(TI_CCxxx0_MDMCFG4,0x4D);   //MODEM CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_MDMCFG3,0x7A);   //MODEM CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_MDMCFG2,0x83);   //MODEM CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_DEVIATN,0x60);   //MODEM DEVIATION SETTING
TI_CC_SPIWriteReg(TI_CCxxx0_MCSM0,0x18);     //MAIN RADIO CONTROL STATE MACHINE CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_FOCCFG,0x16);    //FREQUENCY OFFSET COMPENSATION CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_AGCCTRL2,0x43);  //AGC CONTROL
TI_CC_SPIWriteReg(TI_CCxxx0_FSCAL3,0xEA);    //FREQUENCY SYNTHESIZER CALIBRATION
TI_CC_SPIWriteReg(TI_CCxxx0_FSCAL1,0x00);    //FREQUENCY SYNTHESIZER CALIBRATION
TI_CC_SPIWriteReg(TI_CCxxx0_FSCAL0,0x19);    //FREQUENCY SYNTHESIZER CALIBRATION
TI_CC_SPIWriteReg(TI_CCxxx0_LQI,0x7F);       //DEMODULATOR ESTIMATE FOR LINK QUALITY
TI_CC_SPIWriteReg(TI_CCxxx0_RSSI,0x80);      //RECEIVED SIGNAL STRENGTH INDICATION
TI_CC_SPIWriteReg(TI_CCxxx0_MARCSTATE,0x01); //MAIN RADIO CONTROL STATE MACHINE STATE
TI_CC_SPIWriteReg(TI_CCxxx0_VCO_VC_DAC,0x94);//CURRENT SETTING FROM PLL CALIBRATION MODULE

For 2550

Channel Spacing: 199.95 kHz

Data Rate: 299.927 KBd

Deviation: 101.56 KHz

Xtal: 26 MHz

//
// Rf settings for CC2550
//
TI_CC_SPIWriteReg(TI_CCxxx0_IOCFG0,0x06);    //GDO0 OUTPUT PIN CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_PKTLEN,0x15);    //PACKET LENGTH
TI_CC_SPIWriteReg(TI_CCxxx0_PKTCTRL0,0x04);  //PACKET AUTOMATION CONTROL
TI_CC_SPIWriteReg(TI_CCxxx0_FREQ2,0x5D);     //FREQUENCY CONTROL WORD, HIGH BYTE
TI_CC_SPIWriteReg(TI_CCxxx0_FREQ1,0x93);     //FREQUENCY CONTROL WORD, MIDDLE BYTE
TI_CC_SPIWriteReg(TI_CCxxx0_FREQ0,0xB1);     //FREQUENCY CONTROL WORD, LOW BYTE
TI_CC_SPIWriteReg(TI_CCxxx0_MDMCFG4,0x0D);   //MODULATOR CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_MDMCFG3,0x7A);   //MODULATOR CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_MDMCFG2,0x03);   //MODULATOR CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_DEVIATN,0x60);   //MODULATOR DEVIATION SETTING
TI_CC_SPIWriteReg(TI_CCxxx0_MCSM0,0x18);     //MAIN RADIO CONTROL STATE MACHINE CONFIGURATION
TI_CC_SPIWriteReg(TI_CCxxx0_FSCAL3,0xEA);    //FREQUENCY SYNTHESIZER CALIBRATION
TI_CC_SPIWriteReg(TI_CCxxx0_FSCAL1,0x00);    //FREQUENCY SYNTHESIZER CALIBRATION
TI_CC_SPIWriteReg(TI_CCxxx0_TEST2,0x00);     //VARIOUS TEST SETTINGS
TI_CC_SPIWriteReg(TI_CCxxx0_TEST1,0x21);     //VARIOUS TEST SETTINGS
TI_CC_SPIWriteReg(TI_CCxxx0_MARCSTATE,0x01); //MAIN RADIO CONTROL STATE MACHINE STATE
TI_CC_SPIWriteReg(TI_CCxxx0_PKTSTATUS,0x02); //CURRENT GDOX STATUS AND PACKET STATUS
TI_CC_SPIWriteReg(TI_CCxxx0_VCO_VC_DAC,0x94);//CURRENT SETTING FROM PLL CALIBRATION MODULE

Hi,

As MSK is more spectral efficient, it is better to use for Higher data rates.

Do you have a particular reason why you want to use 2-FSK for 500KBPS?

As per the CC2500 data sheet, 2-FSK should work upto 500KBPs.

You said, you tested up to 300KBPS, 2-FSK without any issue. Is this correct?

You may try with the following setting is SmartRF Studio for 500KBPS.

Set Rx Filter BW  = 812.5KHz

Set Freq Deviation = 126.9KHz (125KHz)

Set Data Rate = 499.878KBPS ( 500kbps)

Please make sure that the Frequency offset is less than 10KHz from the Transmitter to the receiver. If it requires adjust the frequency.

The minimum Receiver Bandwidth required = 2* Freq Dev + Symbol Rate + (4*Crystal ppm*Freq of Operation)

If the above BW calculation becomes more than 812.5KHz then the Receiver may not receive the signal. That's why make sure the Freq offset in between the Transmitter and receiver at minimum. You can measure the tx freq by using CW-Unmodulated more (Set the Spectrum Analyzer Span to < 10KHz for better Freq resolution).

Thanks,

PM

Good day,

Thank your for your response. I need to use 2-FSK due to a certification issue and I need the higher data rate for my application. The answer to the second questions is correct, I did achieved 300k with 2-FSK. I will start with the settings that you give me. I only have some doubt with the 10K Hz offset. when you say "If it requires adjust the frequency." you mean the Base frequency right? and for determine this offset I have to use the continuous RX and TX mode and in the continuous TX, I have turn on the "Frequency Sweep mode" then insert in the Delta Freq bar a value less than 10 k Hz, right or I have misunderstood? Finally, the way to observe that this offset is less than 10 kHz is by observing the RSSI offset with a value less than 10 or what parameter do I have to check in the Continuous RX mode?  

I am sorry for the inconvenience, I am new with this type of communication.

Hope you can help me.

Regards.

Sorry, for the late answer. Yes. I have a good progress with what you told me. Thank you very much.

Sadly, I could not reach the highest because I do not have the equipment that you suggest me but I manage to get higher value.