Hi all, just joined and looking forward to learning from this forum

Hi :smile:

I work as a Systems Analyst and Designer, consulting to the business community here in Melbourne, Australia. I have worked on a range of different IT projects, predominantly software development related. I have done a fair amount of programming, though I would not consider myself a programmer/developer. So with this in mind, I consider myself to be technically minded and have always been interested in electronics and hardware design.

As someone who wants to tinker with electronics in my spare time, I'm interested in developing analogue and digital circuits for all sorts of things.

I am initially interested in discovering more about:

• Digital signal encoding and decoding to "mux" multiple TTL signals (ideally without using a microcontroller)
• Transmitting and Receiving encoded signals over a line (e.g twisted pair) factoring in distance, impedance etc.
• Bi-directional 2-wire RS-485

I'm looking forward to exploring this forum and learning from you all!

Cheers,
Tony

1) CPLD can do what we did 30 yrs ago with quad mux CMOS chips and a whole lot more.. LEarn to use them.
2) twisted pair 12 turns/ft is around 150~200 ohms Zo .. ballpark... from memory.. measure your cable on cap LCR meter at frequency of choice. ie 1MHz 10Mhz or use LC tank circuit and sweep generator to determine C which will affect rise time. RS485 is differential and preferred but 9600 baud per mile is a typical baud rate distance limit for Rs232 unless you use higher power drivers.
3) full-duplex RS485 requires transformer isolation circuits .. see data sheets from Pulse Eectronics.
5) half duplex 2-wire requires flow control such as X-on X-off ASCII characters. with controlled impedance at each end and coax or proper twisted pair with low pf type 7 pf/ft. instead of 15pF/ft

Thanks for the reply. I'm slowly absorbing the information and researching the concepts and technologies raised.

CPLDs look interesting, I'll look into those further. Any suggestions on good CPLD dev/lab boards/kits software/programmers to learn with?

It depends on which camp you belong to. Generally University's are well funded by Altera, Xilinx and Microchip.
Each has their market. Microchip is still the leader in sales volume but the others have their need for high complexity lower volume applications. Such as the $1 CPLD.
Decide which tools you want to learn and how much you want to invest in capital and learning.

If on a budget... how about https://ww1.microchip.com/downloads/en/DeviceDoc/Demo of Barteks CPLD1 development board.pdf ?