The Sinclair QL Forum

Yes.

Generally, it's the write allow position that has the issues. That's pins 1 and 3.

That's slightly cheating as it has a couple of voltage translators on board. However, Dave is gifted in the hardware design area, so a 3.3V i/O based FPGA with some form of input conditioning, or a 5v tolerant device such as the device used in the QL_SD board (Lattice 4000 series?) - I know that's ...

I apologize humbly. I made a typo. I am trying to replace the 8049. Not the 8032. I am looking to do this with an ESP32S. It is TTL friendly as output, and is 5V tolerant on some inputs. That said, a simple level shifter is justified. The keyboard matrix will happily run off 3v3. Serial can be moved...

What I did was just operate the switch repeatedly a couple of hundred times while bathing it in contact cleaner. That doesn't get the crud out of the case, but it does move it around to where the switch makes contact properly again. It's a very standard switch and quite easy to find replacements.

Yeah. I'm going to have to get the scope on it and figure out data rates, etc.

I just want to get keyboard working. The serial implementation isn't worth duplicating as a proper UART can do the job much more cleanly. Sound can come later.

1. Tape loop I was answering a slightly different question than the one you asked. I explained how the system self-tensions, and how it controls and manages slack as the tape stretches over time. As the tape is drawn from the inside, it is pulled tight against the middle of the reel, but the tape lo...

This is a branch off the previous 8049 thread here: http://www.qlforum.co.uk/viewtopic.php?f=2&t=2019 My question this time is to build up a small library of knowledge here about communication between the 8032 and 8049. From the hardware perspective, the link between them is four lines. BAUDX4, ...

I know this is an irregular thing... If you'd like a capable reader and layman programmer to go through and just fix typos and point out areas that are harder to comprehend, I'd happily volunteer. Also, I really appreciated the format and presentation. I know it took time, but it made it much more e...

1. A continuous spool of tape has a finite difference in radius around the spool from the point where it enters the spool to where it exists. This must create a difference in linear speed at entry/exit, albeit small, yet the tape is pulled at a single linear speed (barring fluctuations). Tape stret...

The ULA often fails. All heads are different, and have different impedances. Impedances on AC signals are complex. If Sinclair had thought of it more as an antenna and done a little matching, quality and reliability would have been a lot higher. Often with these heads they used, the impedance ended ...