In this blog post, I present an overview of the "Irwell HF Transceivers" vfo microcontroller software. It is intended as a guide to key features for those who have requested the software or are building the transceiver.
The software and MCU hardware are responsible for generating the VFO signal, oscillator frequencies and to provide control of the various transceiver stages.
The main VFO and controller hardware is based around an affordable STM32 Bluepill microcontroller board.
In the
last blog post, I looked at replacing the three 25MHz xtals that are used for reference clocks on the Si5351 ICs located in the the oscillator module of my digital VFO.
The mod/upgrade to a single TCXO (temperature controlled xtal oscillator) module was carried out and tested in a lash-up fashion with great success. In this blog post, I report on the fabrication of a new PCB that is TCXO ready!
My last blog post was in February of this year (2022) and it is hard to believe we are now at the end of the month of May and close to the halfway point of 2022!
I expect followers of the blog may have been left wondering if my Irwell HF Transceiver project has been abandoned but alas that is definitely not the case!
Welcome to part 5 of my blog post series covering the Digital VFO developed for use with my “Irwell HF Transceiver project”.
In this concluding article, I present the I/O expander module, which interfaces to the STM32 microcontrollers I2C bus, its job is to extend the number of digital outputs available and provide switched logic outputs to drive my BPF and LPF transceiver modules.
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| Illustration of the I/O expander | |
Welcome to part 4 of my blog post series detailing the Digital VFO and RF oscillator module for my “Irwell HF Transceiver" project.
The PCBs have arrived from the fabrication plant so it is now time to get busy with the soldering iron and hopefully call time on this part of the project, or at least for now. Providing there are no issues with the PCBs or hardware, all that remains to be done is software updates to coincide with the future development of the project.
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A trio of G6LBQ VFO boards. |
Welcome to part 3 of my blog post series in which I present details of the hardware for my Digital VFO and RF oscillator module. This is a significant building block for the “Irwell HF Transceiver" project and I Present my buffer amplifiers for the SI5351 ICs and design a PCB to produce a completed working module.
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| My prototype SI5351 buffer & signal splitter circuit! | |
Welcome to part 2 of my blog post series in which I present further details of my Digital VFO and RF oscillator module for the “Irwell HF Transceiver" project. This is a significant building block and is solely responsible for frequency generation and the control of other modules in the project.
Since I posted part 1 on the blog, I have made good progress with the software changes that I outlined. I have added additional commands to JA2GQP’s source code for the I2C Multiplexer and I am now at the stage where I can communicate with two SI5351 devices to produce two chip independent clock signals. In order to achieve this, I have had to make changes to both the main code as well as the SI5351 library file.
For now, I only need to generate two clock signals for my transceiver, one for the VFO and the other for the BFO. This will permit the radio to run as a single conversion superhet in its current state. Once further modules are developed, the receiver will be upgraded to a dual conversion superhet, this will require a third clock signal for the requisite conversion oscillator.
The additional software code required to support a third SI5351 is going to be a bit more difficult for me to implement. I hope to replicate JA2GQP’s BFO oscillator code for this as it includes a routine for calibrating the BFO frequency and saving it to memory. If I can do this, it should also pave the way for implementing an IF shift control.
In
this blog post, I present my digital VFO and RF Oscillator module for the Irwell HF Transceiver project, which is based on the Silicon Labs CMOS SI5351 Clock Generator.
Before we begin, I would like to pay homage to an era in my life which has flourished and brought great happiness, prosperity and achievement.
I make the aforementioned statement with a sense of humbleness and I also feel privileged to have experienced great wealth in the recent flourishing times.
If all this has got you thinking, I have won the national lottery or been a beneficiary to a nice windfall you are excused and forgiven :) The truth is I have only ever been good at making other people wealthy and said people choose to forget what the catalyst was for their wealth status. Those people know who they are, shame on you!
I digress a little as I sailed off course for a moment there but suffice to say I am very happy with my modest lifestyle.
