Well,

I've been fiddling some more with STM32 and have created a DDS based CW & WSPR beacon for 6M.

You can find the details of the project here:


The WSPR code is stolen from Anthony F4GOH, his code and other bits and bobs are on GitHub here:

https://github.com/f4goh/wspr

To counter any drift in the DDS, I've modified my AD9850 board to use an external signal for the clock and configured my Leo Bodnar GPS referenced oscilator to give me 10MHz from output 1 and 125MHz from output 2, thus:


The 125MHz is now used to drive the DDS. I'd be delighted to receive reports from the beacon, the CW signal is on 50.030 and every multiple of 10 mins it sends a 2 min WSPR transmission on 50.293 + 30Hz.

Here's the WSPR beacon RX from G0ORC:


No drift - not even a wobble! Excellent.

Fun, dont you think?

Well,

I've been fiddling some more since the Linear we built a little while ago here.

Some musings below on power meters, directional couplers and measuing RF power:



I hope you are all keeping safe - its very scary out there.

Well,

I've been using the STM32 processor (STM32F103 for those playing along at home) based "Blue Pill" board. This board is compatible with the Arduino IDE and I have been using it with the ILI9341 super duper TFT display module.

This is the board in question:



The STM32 board support can be added easily to the Arduino IDE, just add this line:

https://github.com/stm32duino/BoardManagerFiles/raw/master/STM32/package_stm_index.json

to the preferences screen:


Once you have done that you can then install the STM32 cores from the board manager:


I wrote some very simple code to generate Pi using floating point maths:


Set to calculate 100,000 itterations, the good old Arduino Nano ran this code in 29.60099983215332031250 seconds. This Blue Pill board runs the same calculation in 3.07200002670288085937 seconds. Cooking!

Here' how I have wired the test up for the TFT:


I have used the library called "TFT_eSPI" which is here. In the more modern Arduino IDE you just search for it and install from the library manager.

Once you have done that you need to make a couple of edits to the "User_Setup" file which you can find in the libray directory.

Here's mod 1:


and this is mod 2 - please use pins of your choice here:


Once you have done that all should be well!

Please note that this library and config only works with the Arduino STM32 cores and the HID bootloader.....