programming si570's and si5351's
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Hi Folks, First post.
First, thanks for the work to put together flashforth.
Second, i know there are other hams or amateur radio ops here from my reading. Even the developer.
I am a ham N1GMM and have always loved to build my own transcievers and modules for them. VFO's for instance.
Several have already used assembler (very old asm from Microchip) and I have no interest to rework 5000 lines of assembler (.asm) to the newer assembler .as ... Since I needed a project, and have always wanted to use forth for this (I used it in my sun microsystem days) to program and create a simple interface for an encoder and dot maitrix display to drive the chips for mainly HF radio (1.8mhz->30mhz) using forth.
I have (actually several) scamps (3/3E) and several microchip and avr boards (328)..
Has any here done this type of thing before or are any interested in doing such a thing?
Thought I would ask.. I am going ahead with this no matter what.. and will post things here or on my document server for my reference (dokuwiki).
Best to all and 73 to all the hams.
Guy, N1GMM
Hi Guy.
At least I am interested. Just today I made an adjustment to my homebrew HF receiver. I have come to the conclusion that the most efficient way of making a LO is to use the high quality SI5351 board from SV1AFN that has minimal birdies and a quite stable XTAL. The "standard" SI5351 boards have a lot worse level of spurious responses due to inferior ground plane design.
Minimizing the current output from SI5351 reduces the spurious levels a bit further, so today I added a J310 source follower and a 4:1 transformer to feed the TUF-1 DBM, instead of driving it directly from the SI5351 output.
Have you seen my code examples for a HF receiver (45MHz/455KHz IFs)? It uses 32/64 bit scaling operators to accurately program the SI5351. UQ* and UQ/MOD is available on all PICs including the SCAMPs. Not on the AVR, mainly because I had no need for that.
I have built several variations on the theme. Here is the code for one of the receivers.
https://sourceforge.net/p/flashforth/code/ci/master/tree/pic18/rxnew/
It uses the SI5351 as LO1(45-67MHz) and LO2(44545KHZ). The BFOs around 455KHz are
produced by a PIC18 NCO. I have another design where also the BFOs are produced by the SI5351. The PIC18 also handles switching of filters, the rotary encoders and the I2C display and the A/D for the S-meter. There is also a a BC FM receiver on the board.
From time to time I have considered designing a SI570 board since the chip has slightly lower phase noise, but I do not like the high current consumption of it. And the SI5351 turned out to be good enough, even with three different frequencies being generated.
73s de Mike OH2AUN