Wireless communication

[chandpriyankara]

hey guys...,
why dont we talk on other available easy to use wireless communication tools for robotics and related application?

like:
TWS434 + RWS 434,
Bluetooth radio Modules,
..
etc.

[charlie65]

I am working on experimenting with the CC2500 and have planned a PCB for that.

Attached please find the schematic and Overlay of the Test Jig that I have designed.

I am awaiting for the PCB's, when I have them I would post further development.

There are some minor discrepancies between the schematic and Overlay, but that should do.

regards.

[ikalogic]

Hi charlie.. that's really interesting.. keep us updated!

[chandpriyankara]

yr.... keep it up boy!

[chandpriyankara]

i think this module support for both bit wise operation and packet mode operation.
also may support FEC(Forward Error Correction), channel selection, etc.

[charlie65]

This (module) is the best it can get on RF, just a little understanding is required and you can work it over. I had successfully worked the CC1100 module and I thought the CC2500 was similar , so I ported my code to this module and it did not work (obviously) . So now I have a test jig for just this module and have studied all the resistors and would go ahead and experiment with this module.

I was impressed seeing a demo of the Phillips Living Lights (Mood light / RGB Fader) controlled with a CC2500 somewhere on the net (Youtube). I am now planning to implement this using CC2500.

More on it as I progress.

regards

[anwr.ah]

Thanks a lot for the schematics... can you plz post code too? i mean i am finding it hard to configure the cc2500 registers. plz help.. thanks

[charlie65]

Sorry, at present , even I am struggling to get the code to work. The registers are a mystery to configure.

Hope some one has mercy and post the register listing.

regards

[anwr.ah]

I have some sample code for MSP430 microcontroller interface to cc2500 provided as a sample code by chipcon itself. I am trying to modify that.

Plz tell me if I am right or wrong...
What i think is to be done is -
1. Get register config from smart rf studio.
2. to configure registers, first send register address and then the corresponding register value, via the spi interface.
3. after configuration is done, send data to be transmitted in burst mode..

Please tell if I am going right.

As of now, I have a little work with the hardware itself too.

[charlie65]

IMHO, first and foremost, have a printout of the datasheet handy for easy reference. Each of the register values are tricky. You need to know what each of the registers do and mean. Because, Smart RF Studio will just give you register values, assuming that you know what they mean.

I have some BASIC code subroutines , that may help you understand the procedure.

Setup:

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    Dim CC_TE       As PORTC.4          ' OUTPUT, Chipcon Tx EN
    Dim CC_CS       As PORTC.3          ' Output, Chipcon Chip Select Active LOW 
    Dim CC_SCLK     As PORTC.1          ' Output, Chipcon SPI SCLK               
    Dim CC_MISO     As PORTC.2          ' Input,  Chipcon SPI Data Output         
    Dim CC_MOSI     As PORTC.0          ' Output, Chipcon SPI data Input         
    Dim STAT_LED    As PORTC.5          ' LED OUTPUT (SOURCE), ACTIVE HIGH       
    Dim CC_Status   As Byte             ' Chipcon status register value                                         
    Dim CC_Addr     As Byte             ' Chipcon register address value                                       
    Dim Reg_WR      As Byte             ' Chipcon register write value                                         
    Dim INDEX       As Byte                                                                             



Very first you reset the chip.

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CC_RESET:
    High STAT_LED : CC_TE = 0 : CC_SCLK = 1 : CC_MOSI= 0
    CC_CS = 0 : CC_CS = 1 : DelayUS 42 : CC_CS = 0
    While CC_MISO = 1 : Wend
    CC_Addr = _SRES : Reg_WR = _SNOP : GoSub load
    While CC_MISO = 1 : Wend
    DelayMS 500 : Low STAT_LED
    RSOut "==> MODULE RESET <==",CR
Return


Then you program all the registers with the value you got from Smart RF Studio.

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multi_reg_write:
    High STAT_LED : Low  CC_TE      ; VISUAL INDICATION
    ; bit 7 of address byte clear to write to a register.
    ; bit 6 of address byte set to write to group of regs.
    'CC_Addr = (CC_Addr | %01000000) :
    DelayUS 10
    CC_CS = 0                       ;Enable register programming
    SHOut CC_MOSI,CC_SCLK,1,[%01000000]
    For INDEX = 0 To 46
        SHOut CC_MOSI,CC_SCLK,1,[INFO[INDEX]]
    Next INDEX
    CC_CS = 1 : Low STAT_LED        ;End register programming
Return


The Speed of the SPI is also critical, a slower Xtal will not help.

After doing this, it is important to calibrate the VFO

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CC_Addr = _SCAL : Reg_WR = _SNOP : GoSub reg_write  ' CALIBRATE VCO


Now that you are ready, put the module in Rx mode

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CC_Addr = _SRX : Reg_WR = _SNOP : GoSub reg_write   ' ENABLE RECEIVER


Status register is the most Important register that you need to monitor after every read/write operation

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RD_STAT:
    'CC_Addr = (CC_Addr | $C0)       ; Make addr 6 and 7 bit 1 to read a
    CC_Status = 0                    ; CC1100 status register.
    CC_CS = 0  ;Enable register programming
    While CC_MISO = 1 : Wend
    DelayUS 100
    SHOut CC_MOSI,CC_SCLK,1,[%1100-0000]
    DelayUS 10
    SHIn CC_MISO,CC_SCLK,0,[CC_Status]
    CC_CS = 1       
    RSOut "Status Byte ==>",SPACE,Bin8 CC_Status ,SPACE,Dec2 CC_Status, CR
    CC_Addr = _MARCSTATE : GoSub reg_read
    RSOut "MARCSTATE",SPACE,"0xF5", SPACE,"==> 0x",Hex2 Reg_WR,SPACE,CR
Return


When you are ready for Rx, take the CC_CS high. now when you Tx from another module, the data comes and gets filled in Rx_buffer and CC_MISO acts as an int pin to give you that indication that there's mail in your mail box (Rx_buffer). So when you have a mail, you go and check the Rx_Buffer.

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READ_FIFO:

    High LED1 : High LED2 : High LED3 : High LED4
    High STAT_LED : Low  CC_TE      ; VISUAL INDICATION
                                    ; CC1100 registers
    While CC_MISO = 1 : Wend        ; WAIT FOR SO TO GO LOW
    CC_CS = 0                       ;Enable register programming
    SHOut CC_MOSI,CC_SCLK,1,[%11111111]
    DelayUS 10
    For INDEX = 0 To 2              ; BUFF_LEN
        SHIn CC_MISO,CC_SCLK,0,[INFO[INDEX]]
    Next INDEX
    CC_CS = 1                       ;End register programming
    For INDEX = 0 To 2              ; BUFF_LEN
        RSOut "INDEX",SPACE,":",Dec INDEX ,SPACE,"==> ",Dec INFO[INDEX],CR
    Next
    If INFO[0] = 1 Then Low LED1
    If INFO[0] = 2 Then Low LED2
    If INFO[0] = 3 Then Low LED3
    If INFO[0] = 4 Then Low LED4   
    CC_Addr = _SIDLE : Reg_WR = _SNOP : GoSub reg_write ' IDLE MODE
    CC_Addr = _SFRX : Reg_WR = _SNOP : GoSub reg_write  ' FLUSH RX BUFFER
    CC_Addr = _SRX : Reg_WR = _SNOP : GoSub reg_write   ' GO BACK TO RX
    RSOut CR,CR : Low STAT_LED
Return

for sending a mail or data, I use the following code -

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KEY4:
        High STAT_LED : Low  CC_TE
        While SW4 = 0 : Wend
        CC_Addr = _SIDLE : Reg_WR = _SNOP : GoSub reg_write : DelayMS 100
        CC_Addr = _SFTX : Reg_WR = _SNOP : GoSub reg_write  ' FLUSH TX BUFFER
        DelayMS 100
        ' ADD DATA TO THE FIFO
        CC_Addr = _FIFO : Reg_WR = 4 : GoSub reg_write : DelayMS 100
        CC_Addr = _FIFO : Reg_WR = 8 : GoSub reg_write : DelayMS 100
        CC_Addr = _FIFO : Reg_WR = "D" : GoSub reg_write  : DelayMS 100
        High CC_TE : DelayMS 100                              ' ENABLE PA
        CC_Addr = _STX : Reg_WR = _SNOP : GoSub reg_write   ' ENABLE TX
        DelayMS 700 : Low  CC_TE : Low STAT_LED               ' DISABLE PA
        CC_Addr = _SIDLE : Reg_WR = _SNOP : GoSub reg_write ' IDLE MODE
        GoSub EN_RX
Return

This code is just for 1 key, you can replicate it for as many keys you want.

some more data which you can use for initialization

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; CC1100 STROBE ADDRESSES
    Symbol _SRES        =   $30     ;RESET CHIP
    Symbol _SFSTXON     =   $31     ;CALIBRATE FREQUENCY SYNTHESIZER & TURN ON
    Symbol _SXOFF       =   $32     ;TURN OFF CRYSTAL OSC.
    Symbol _SCAL        =   $33     ;CALIBRATE FREQ SYNTH AND TURN OFF
    Symbol _SRX         =   $34     ;ENABLE RECEIVER
    Symbol _STX         =   $35     ;ENABLE TRANSMITTER
    Symbol _SIDLE       =   $36     ;GO INTO IDLE MODE
    Symbol _SAFC        =   $37     ;PERFORM AFC ADJUSTMENT
    Symbol _SWOR        =   $38     ;START WAKE ON RADIO POLLING
    Symbol _SPWD        =   $39     ;ENTER POWER DOWN MODE WHEN CHIP SELECT HIGH
    Symbol _SFRX        =   $3A     ;FLUSH RX FIFO BUFFER
    Symbol _SFTX        =   $3B     ;FLUSH TX FIFO BUFFER
    Symbol _SWORRST     =   $3C     ;RESET REAL TIME CLOCK
    Symbol _SNOP        =   $3D     ;NO OPERATION

; iNITIALIZE ON BOARD TRANSCEIVER REGISTERS
    INFO[0] = $2E        ' 0x00 GD02 Pin Setting                                   
    INFO[1] = $86        ' 0x01 GD01 Pin Setting                                   
    INFO[2] = $06        ' 0x02 GD00 Pin Setting                                   
    INFO[3] = $07        ' 0x03 FIFOTHR - RX,TX FIFO Thresholds                   
    INFO[4] = $D3        ' 0x04 SYNC1 - Sync Word High Byte                       
    INFO[5] = $91        ' 0x05 SYNC0 - Sync Byte Low Byte                         
    INFO[6] = $03        ' 0x06 PKTLEN - Packet Length                             
    INFO[7] = $04        ' 0x07 PKTCTRL1 - Packet Automation Control               
    INFO[8] = $04        ' 0x08 PKTCTRL0 - Packet Automation Control               
    INFO[9] = $00        ' 0x09 ADDR - Device Address                             
                           
    INFO[10] = $00       ' 0x0A CHANNR - Channel Number                                 
    INFO[11] = $06       ' 0x0B FSCTRL1 - Freq Synth Control                           
    INFO[12] = $00       ' 0x0C FSCTRL0 - Freq Synth Control                           
    INFO[13] = $0C       ' 0x0D FREQ2 - Freq Control Word High Byte                     
    INFO[14] = $1D       ' 0x0E FREQ1 - Freq Control Word Mid Byte                     
    INFO[15] = $89       ' 0x0F FREQ2 - Freq Control Word Low Byte                     
    INFO[16] = $F6       ' 0x10 MDMCFG4 - Modem Control 4  > Sets RXBW                 
    INFO[17] = $83       ' 0x11 MDMCFG3 - Modem Control 3                               
    INFO[18] = $03       ' 0x12 MDMCFG2 - Modem Control 2                               
    INFO[19] = $A2       ' 0x13 MDMCFG1 - Modem Control 1                               
    INFO[20] = $F8       ' 0x14 MDMCFG0 - Modem Control 0                               
    INFO[21] = $15       ' 0x15 DEVIATN - Deviation Setting                             
    INFO[22] = $07       ' 0x16 MCSM2 - Radio State Machine Config                     
    INFO[23] = $1F       ' 0x17 MCSM1 - Radio State Machine Config                     
    INFO[24] = $04       ' 0x18 MCSM0 - Radio State Machine Config                     
    INFO[25] = $16       ' 0x19 FOCCFG - Freq Offset Compensation                       
    INFO[26] = $6C       ' 0x1A BSCFG - Bit Sync Config                                 
    INFO[27] = $03       ' 0x1B AGCTRL2 - ACG Control 2                                 
    INFO[28] = $40       ' 0x1C AGCTRL1 - ACG Control 1                                 
    INFO[29] = $91       ' 0x1D AGCTRL0 - ACG Control 0                                 
    INFO[30] = $87       ' 0x1E WOREVT1 - Wake On Radio Event 0 Timeout                 
    INFO[31] = $6B       ' 0x1F WOREVT0 - Wake On Radio Event 0 Timeout                 
    INFO[32] = $F8       ' 0x20 WORCTRL - Wake On Radio Control                         
    INFO[33] = $56       ' 0x21 FREND1 - Front End RX Config                           
    INFO[34] = $10       ' 0x22 FREND0 - Front End TX Config                           
    INFO[35] = $E9       ' 0x23 FSCAL3 - Freq Synth Calibration 3                       
    INFO[36] = $0A       ' 0x24 FSCAL2 - Freq Synth Calibration 2                       
    INFO[37] = $00       ' 0x25 FSCAL1 - Freq Synth Calibration 1                       
    INFO[38] = $1F       ' 0x26 FSCAL0 - Freq Synth Calibration 0                       
    INFO[39] = $41       ' 0x27 RCCTRL1 - RC oscillator configuration                   
    INFO[40] = $00       ' 0x28 RCCTRL0 - RC oscillator configuration                   
                                 
    INFO[41] = $59       ' 0x29 FSTEST - Freq synthesizer calibrate control             
    INFO[42] = $7F       ' 0x2A PTEST - Production test                                 
    INFO[43] = $3F       ' 0x2B AGCTEST - AGC test                                     
    INFO[44] = $81       ' 0x2C TEST2 - Various test settings                           
    INFO[45] = $35       ' 0x2D TEST1 - Various test settings                           
    INFO[46] = $09       ' 0x2E TEST0 - Various test settings                           



I had successfully worked the CC1100 using parts of the above code, but it simply did not work for the CC2500. That meant, I had to break my head (Study) the data sheet for the CC2500 and see what should be different.

The important thing is the register values and I was looking at shortcuts trying to copy & paste from other working example. It did not work. But , given some time and the hardware (which I have ready) , I can surely crack it.

I now have got some long range CC1100 modules and I would now be concentrating on them rather than the CC2500. But CC2500 should have been more easier than the CC1100, but don't know.

So you can give it a shot and tell me how it goes.

regards

[anwr.ah]

Thanks a lot for the code. Its helpful.

This is how my connections are. Point out if there is any mistake.

CC2500_2.jpg (21.82 KB) Viewed 91 times

Writing code in C now. Will post it soon.

[charlie65]

No, it does not tally, anyway, I have uploaded the Datasheet of my module.

Although it looks the same, it may be different, but its important, not to mess around with it , unless you know the exact pin out.

All the best for the code and do share your findings. May help someone (and me off-course) .

regards