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controls (DIP switch, button, and LED) are your whole User Interface to ProgRock!
You will need to move the DIP switches with a screwdriver blade-tip
– they are too small to set with your
fingers!
The rest of this document assumes holding the ProgRock PCB for programming purposes in the
orientation shown in these photographs.
When programming ProgRock please remove the 1pps connection to the GPS, if you are using the
GPS. It can interfere with the button debounce logic. The 1pps input should be grounded during
programming of ProgRock.
The DIP switches should always be set to OFF at Power-up and when you have finished
programming! ProgRock cannot test the Si5351A (see start-up procedure below), or do GPS
calibration, when the DIP switch on the left (labelled “1” in the above photograph), is ON!
6.2
Power-up procedures
On applying power to ProgRock, the red LED is illuminated for a short time.
The first operation undertaken by the ProgRock microcontroller on power up, is to check the connection to
the Si5351A chip via the I2C bus. It then checks that it can read the 27MHz reference frequency (divided
down) on the Clk2 output. If the I2C communication fails or the reference frequency cannot be read, then
the red LED will remain illuminated. No further actions will be taken, and the switches, buttons, and bank
select inputs are all ignored. If the microcontroller cannot operate the Si5351A chip, then nothing else can
be done. You will need to investigate the issue and resolve it, before proceeding. The system must be
reset by removing and re-applying power, to try again.
The DIP switches must be set to OFF at power-
up and when using the GPS calibration option!
You might wish to program the ProgRock frequency list without the Si5351A Synth module plugged in. For
example if you have fitted SMA connectors to the Si5351A Synth module, then the 4-way DIP switch and
button will be a bit hard to access with your fingers. When the Si5351A Synth module is not plugged in, the
above error check will fail, and ProgRock will be st
uck in the “error state” with the red LED illuminated.
To avoid this problem, and allow you to program the frequency list without the Si5351A Synth module
plugged in, you can BYPASS the error check. To bypass the error check, press the button (S2) while
powering up ProgRock. When you have done this, the microcontroller will not attempt to communicate with
the Si5351A chip again, until power is removed and re-applied.
Finally if all is well, you have programmed frequencies, and the Si5351A Synth module is all working
properly
– the microcontroller will set up the Si5351A chip to output the frequencies you chose.
