USRP: ClockTamer Control Protocol

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Kita dapat mengontrol ClockTamer melalui USB atau SPI. Jika tersambung ke USB, ClockTamer akan mengemulasi serial port, oleh karenanya kita dapat mengontrolnya menggunakan terminal emulator, baik dari script atau program. Sambungan SPI digunakan jika ClockTamer tersambung ke USRP dan sangat berguna jika kita tidak ingin menggunakan dua kabel USB dari USRP ke komputer yang kita gunakan.

ClockTamer menggunakan protokol berbasis text dan pada dasarnya sama baik itu untuk interface ClockTamer USB maupun SPI. Protokol versi USB dan SPI berbeda hanya pada cara jawaban dari ClockTamer di kirim. Jika menggunakan sambungan SPI kita perlu poll untuk memperoleh jawaban, seperti di jelaskan di halaman interface SPI, di Linux sebelum kita melakukan pertukaran data sebaiknya kita matikan echo dari ClockTamer serial device. Melalui command line kita dapat mematikan melalui perintah berikut, 

stty -F /dev/ttyACM0 -echo

Dimana /dev/ttyACM0 adalah ClockTamer serial device file.

Pendek kata, protokol ClockTamer mempunya fitur:

  • It's strictly master/slave, with ClockTamer being slave. This means, that ClockTamer can only reply to commands sent by host and can't issue any commands or queries to host.
  • All commands and answers are ASCII strings, terminated by CR/LF. This makes it easy to command ClockTamer in interactive mode with your favorite terminal emulator program.
  • Every command from host is followed by answer from ClockTamer, i.e. protocol is synchronous. It's like in SD/MMC - if you've sent a command you should wait until answer is received before issuing next command. If you haven't received answer after some long time, something went wrong and it's a bug. It's recommended to reset ClockTamer and try again. And don't forget to report bugs here!

For impatient...

If you just want to start using your ClockTamer without getting into all fine details, here is the way to go: 

SET,,OSC,<osc_freq>
SET,,OUT,<out_freq>

where you should replace:

  • osc_freq with the frequency (in Hz) of (VC)TCXO installed on your ClockTamer, e.g. something like 20000000. Note that you can calibrate your ClockTamer by slightly adjusting osc_freq. Read ClockTamer calibration page for detailed instructions.
  • out_freq with desired output frequency (in Hz).

If you're satisfied with your settings, you can store them in EEPROM to be used after reboot: 

STE

Commands and answers structure

Every command have format

CMD[,TYP[,DET[,value]]]<CR><LF>

where

CMD - three letter command class. Must be non empty string.

TYP - three letter command target type. May be empty string, even if DET or value is present (e.g. SET,,OSC,10000200).

DET - three letter command target details. May be empty string, even if value is present (e.g. PIN,LED,,0).

value - decimal or hexadecimal value. Decimal values start with a digit (e.g. 54781), hexadecimal values start with 'x' letter (e.g. x01af3d).

Depending on command class, later fields may be omitted completely, e.g.:

LDE - only CMD is present INF,,OSC - CMD, TYP and DET are present with TYP as empty string

Answer format is as following: 

   If command does not require a value to be returned, then answer is

   OK<CR><LF>

   If command returns a value, answer has structure same as command:

   CMD[,TYP[,DET[,value]]]<CR><LF>

   where CMD, TYP and DET repeats the respective fields in the command. 

   If command can't be parsed, error is returned:

   SYNTAX ERROR<CR><LF>

Command classes Register ("REG")

Writes value data to appropriate registers of chips via MicroWire bus. Using this commands you can control every aspect of clock generation in manual mode. Allowed target type and detail combinations: TYP DET value Description LMK <empty> 32bit value Write to LMK (clock distributor) chip registers LMX <empty> 24bit value Write to LMX (PLL+VCO) chip registers (if LMX is present) DAC <empty> 16-24bit value Write to DAC (Digital-to-Analog Converter) chip registers (if DAC is present)

Pin ("PIN")

Controls pins of chips. Allowed target type and detail combinations: TYP DET value Description LMK ENB 0/1 ENABLE pin of LMK (clock distributor) chip. LMK GOE 0/1 GOE pin of LMK (clock distributor) chip. LMX SYN 0/1 SYN pin of LMX (PLL+VCO) chip. LED <empty> 0/1 Turn LED on/off.

Set ("SET")

Easy to use setting of output frequency, setting oscillator calibration value, changing algorithms internal variables. The most useful target type and detail combinations: TYP DET value Description <empty> <empty> <empty> Write all control registers from MCU RAM to LMX and LMK chips. <empty> OSC integer Set oscillator frequency. Used when oscillator is changed, when external frequency source changed its frequency or to calibrate oscillator. Control registers of LMK and LMX are recalculated and written to the chips with this command. <empty> OUT integer Set ClockTamer output frequency. Control registers of LMK and LMX are recalculated and written to the chips with this command. <empty> AUT 0/1 If set to 1 ClockTamer will load all variables from EEPROM and start generator on boot. LMK <empty> <empty> Write all control registers of LMK to the chip. LMK PRT integer Change value of LMK output mask. See description of LMK_OutMask EEPROM register for details. Control registers of LMK are written to the chip with this command. GPS SYN <empty> One-time synchronization to GPS. GPS AUT 0/1 If set to 1 ClockTamer will keep clock synchronized to GPS.

Save ("SAV")

NOT IMPLEMENTED YET Defaults ("DEF")

NOT IMPLEMENTED YET Info ("INF")

Get value of the selected variable. Every variable (specified in DET), usable with SET has its INF counterpart. There is no NFO command with empty DET, though.

There are also a set of variables for debugging purposes only. You don't need to touch them if you don't change the firmware. Also their meaning may change from one firmware version to another without API version change. Currently available target type and detail combinations: TYP DET value Description GPS DIV <empty> Debug output. Value of divider of LMK output, routed to MCU input. GPS KBT <empty> Debug output. GPS R00 <empty> Debug output. GPS R01 <empty> Debug output. In ClockTamer-1.2 it gives you a number of received 1pps ticks. If this value is increasing, then GPS lock is acquired. GPS R02 <empty> Debug output. GPS R03 <empty> Debug output. In ClockTamer-1.2 it gives you calculated output frequency, multiplied by 32, i.e. Fout = R02/32. GPS MAX <empty> Debug output. GPS MIN <empty> Debug output.

Version ("VER")

Get firmware and protocol versions.

Example:

ClockTamer SW=1.23 API=1

Hardware information ("HWI")

Get detailed information about installed hardware options. This information is stored in EEPROM and may be altered only if ClockTamer is flashed over SPI. Flashing over USB can not change EEPROM data.

Values shown in HWI string incude: LMX= Type of LMX2531 VCO+PLL. Can be "2080" for LMX2531LQ2080E or "1515" for LMX2531LQ1515E. Most ClockTamers have LMX2531LQ2080E. LMK= Type of LMK01000 Clock Buffer, Divider, and Distributor. Can be "1000" for LMK01000, "1010" for LMK01010 or "1020" for LMK01020, but is usually LMK01010. OSC=

FOSC= Frequency of the reference TCXO or VCTCXO in MHz. Possible values are 10, 20 or 26. GPS ClockTamer has GPS module installed if GPS is present in HWI. VCTCXO ClockTamer use VCTCXO with DAC instead of TCXO with VCO+PLL is VCTCXO is present in HWI.

Example of HWI for a ClockTamer with LMX2531LQ2080E, LMK1010, 20MHz TCXO and GPS:

LMX=2080 LMK=1010 OSC=20 GPS

Reset ("RST")

Sends reset command to LMK and LMX and clears variables in MCU RAM, but does not affect EEPROM. To start output generation after RST you can execute "SET,,OSC,<val>", "SET,,OUT,<val>" or "LDE"+"SET". Load EEPROM ("LDE")

Loads previously stored values from EEPROM to RAM. This command does not push them to LMK and LMX chips, so you should execute SET command manually.

TYP, DET and value should be empty. Store EEPROM ("STE")

Stores all values to EEPROM. This values will be used by default after ClockTamer reboot. They can also be loaded to RAM at any time with LDE command.

TYP, DET and value should be empty. EEPROM variables list

Variable Description Fosc Oscillator frequency Fout Output frequency VCO_MIN Parameter for calculation of VCO registers for LMX. Shouldn't be changed unless you change LMX on your unit. VCO_MAX Parameter for calculation of VCO registers for LMX. Shouldn't be changed unless you change LMX on your unit. VCO_Kbit Parameter for calculation of VCO registers for LMX. Shouldn't be changed unless you change LMX on your unit. LMK_OutMask Enable/disable output generation on specific LMK outputs. Set bit in the mask to 1 to enable corresponding output and to 0 to disable it. E.g. x60 value will enable 5 and 6 outputs and disable all others. See outputs numbering below. AutoFreq Autostart generating output on boot. DacValue DAC value if VCTCXO is used. AutoGPSSync Continuously synchronize clock to GPS.

Outputs numbering ClockTamer-1.0

If you look at ClockTamer so that "ClockTamer v1.0" label reads normally, then outputs are numbered in the following way:

2 0 

 .---.
 |LMK|  7
 .---.
        6

4 5 6*

where 0,2,4,5,6 - places for U.FL connectors, 6* - a place for SMA connector. Outputs number 1 and 3 are not present on PCB. In default configuration outputs number 0 and 2 are LVDS, while 4,5,6 are LVPECL/CMOS. ClockTamer-1.1 and ClockTamer-1.2

Outputs numbering is as shown on the picture:

Tamer-gui-pic.png

Outputs 1 and 6 and CMOS, while outputs 0, 3, 4, 5 and 7 are LVDS or half-LVDS. Refer to Features and technical specification page for more information about half-LVDS outputs.


Referensi

Pranala Menarik

Persiapan

OpenBTS 2.6

OpenBTS 2.8

Ettus E110

Lain Lain

Catatan Legal dan Pendukung

Catatan Sejarah

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