Howdy friends,
I am attempting to build Mike Willeal's keyboard ASC to PS2 Converter. I finally overcame the battle of the Gerber files but had to use PCBWay instead of my usual PCB fab company, OSH Park. While waiting for the PCB to arrive, I wanted to start programming the ATtiny2313.
While I have programmed some microcontrollers in the past, I am rather confused about this process and most specifically the calibration process. The guidance on the page isn't detailed enough for my experience level and the supporting document assumes you have a pre-programmed 2313. I’m not an EE, just a hobbyist who is still learning a lot. Perhaps some folks can assist.
I will start with this question, as its answer may solve a lot of my issues surrounding calibration.
Is the calibration process unnecessary if you plan to only use the PS2 port for a keyboard input?
Mark
It's common issue with many of these microcontrollers that they do have very imprecise internal oscillators. Therefore, most designs usually use an external oscillator (a crystal), if enough pins are available and an exact clock source is required. And for an RS232 port you need to have a fairly accurate frequency source, otherwise the system will not be able to properly send or receive.
However, for PS/2 it doesn't matter. There is no exact frequency required for PS/2. It's using separate signals for clock and data. Data is transmitted on the falling edge of the clock signal - whenever that is.
In short, yes, if you are not planning to use the RS232 port of this adapter, you can forget about the clock calibration.
Thanks for the confirmation and the information.
Much appreciated.
Merry Christmas
So this may seem like a weird question. Looking at the board (schematic was not published), it seems like I could leave the MAX202 RS232 and associated caps off and it should still work. Do you know if that is a correct assumption?
Mark