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QRP Labs “ProgRock” programmable crystal
1. Introduction
Thank you for purchasing this QRP Labs kit. This kit comprises two modules:
Si5351A Synthesiser module kit
ProgRock controller kit for the Si5351A Synthesiser
You need to download the assembly instructions for the Si5351A synthesiser module kit separately. The
synth kit plugs into the ProgRock controller kit’s two 10-pin header sockets. This document describes the
assembly and operation of the ProgRock kit.
This kit gets its name “ProgRock” from the potential use as a programmable crystal replacement. A lot of
applications arise where one needs a crystal of an unusual frequency, which cannot be found at any
supplier or in the junk box. Custom crystal manufacture is expensive and time-
consuming. So “ProgRock
can replace those unusual crystals! ProgRock provides THREE independent outputs, and 8 banks of
selectable frequencies.
Additionally, by connecting a 1 pulse-per-second (1pps) signal from a GPS receiver (such as the QRP
Labs QLG1 GPS receiver kit), the ProgRock controller will GPS-discipline the Si5351A PLL reference
frequency, correcting for any calibration error and temperature-related frequency drift.
Programming of the ProgRock frequencies is by a 4-way DIP switch and button. You will enter the
frequencies in binary coded decimal, one digit at a time. A little cumbersome, but you’ll soon get used to it
and get fast at it. Anyway this kit is not a VFO
– QRP Labs has a different kit for that – this kit is ProgRock,
a crystal replacement which does not need to be reprogrammed very often. The good news of course is
that all the settings you enter, are stored in the microcontroller’s EEPROM, so that they are ready next
time you power up your project.
A short summary of ProgRock features:
3 independent 3.3V p-p squarewave outputs (2 if you use GPS discipline)
8 selectable “banks” of frequencies, chosen by 3 input control signals
Frequency range 3.5kHz to 200MHz
Extended frequency range up to approx. 300MHz if you don’t mind violating the Si5351A datasheet
specifications
GPS frequency discipline using 1pps from a GPS receiver
Unique power supply noise filter circuit designed by Alan Gray G8LCO
Power supply voltage 5V, or using LM317LZ regulator (supplied), range is 5-12V DC
Minimalist configuration user interface using 4-way DIP switch, push button, and LED
Easy construction, no surface-mount components to solder (Si5351A already pre-soldered)
Recommended approach to building the kit:
This is a simple design but there are several features
which provide a great deal of flexibility.
Read this WHOLE manual and understand it!
BEFORE you start
to build it
– so that you know what hardware options you want. Follow the assembly instructions carefully!
