The SigTest, short for signal test, is a test program that can be used for evaluating the Si5351A. There is a simple textual Man Machine Interface (MMI) via the USB port.

SigTest does not rely on GPS signals and the frequencies generated are therefore not concurrently GPS calibrated. The reason is that for testing purposes you do not want the Si5351A to change frequency, because the reference frequency was changed, behind your back.

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Display

To setup the type of display used please use the “wr display” command. If you want to change what is shown on the display please edit the display.cpp file.

Please see the display page for more information.

LCD 16×2

The display shows the two frequencies, the drive strengths [mA], the output mode and the reference drive strength [mA].

Example of an LCD 16×2.

LCD 20×4

The display shows the two frequencies, the drive strengths [mA], the output mode and the reference drive strength [mA].

Example of an LCD 20×4.

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Man Machine Interface (MMI)

The MMI is done via the USB port, 9600 Baud, 8 bits, no parity and one stop bit, using a terminal program (e.g. Arduino IDE Serial Monitor, Termite Terminal (Windows), CuteCom (Linux) or Terminal (Mac OS)). Please connect the RFzero via a USB B cable to your computer and connect the terminal program to the right COM port in the terminal program. The RFzero identifies itself as an Arduino Zero (Windows Device Manager).

If you don’t see the RFzero> prompts please press the enter key. When you want to execute a command you don’t have to enter the RFzero> prompt but only the command and parameters after the >.

All input to the RFzero must be in lowercase.

To see the available commands please enter a question mark at the RFzero prompt and press the <Enter> key.

RFzero> ?

The most common commands are

wr reset

set output to push – pull, frequency to 10 MHz MHz, RF on 8 mA, OMDs to integer mode and reference to normal.

wr t1 MODE

to set the T1 hardware mode where MODE is: 0: transformer, 1: combiner, 2: none

wr display MODE

to set the display mode where MODE is: 0: none, 1: LCD 16×2 on JP12, 2: LCD 20×4 on JP12, … for more information after changing display mode the program has to be reset!

wr pcf8574 ADDR

to set the PCF8574 I2C address: 0, 0x20-0x27 or 0x38 to 0x3F.

rd cfg

to list the current configuration.

wr freq FREQ

to set the frequency in Hz where FREQ is from 2289 Hz to 300 MHz, and where [PORT] is optional and if used either 0 or 1.

wr rf LEVEL [PORT]

to set the RF output level where LEVEL is 0: off, 1: on, 2: 2 mA, 4: 4 mA, 6: 6 mA and 8: 8 mA, and where [PORT] is optional and if used either 0 or 1.

rd fref

to read the reference frequency. Not measured!

wr ref LEVEL

to set the RF output level where LEVEL is 0: off, 1: on, 2: 2 mA, 4: 4 mA, 6: 6 mA and 8: 8 mA.

wr ssc FREQ AMPL

to enable centered spread spectrum at frequency FREQ where AMPL is: 0.1 to 1.5 percent. If FREQ is 0 then spread spectrum is disabled.

wr vco FREQ

to set the VCO start frequency in Hz where FREQ is from 405 MHz to 600 MHz.

wr output MODE

to set the output mode where MODE is: 0: push-pull, 1: two-tone, 2: I/Q and 3: H3E.

wr reg ADDR VALUE

to write the VALUE (hex) to the register at ADDR (dec).

rd reg ADDR

to read the value (hex) at the register ADDR (dec).

rd regs

to read registers 26-33 and 42-49/50-57.