Bit by bit I’m slowly getting it tested and debugged. There were a few problems with pins crossed but maost of those cuts/jumpers were made and it’s definitely running the KIM monitor program from the USB terminal interface, so it’s a functioning system. Today I need to create a new EEPROM that puts the KIM monitor back in low memory where it belongs, then put my extended monitor in high EEPROM to get some much needed tools (memory tester) working.
There are still more problems to fix and one of my “improvements” turned out to be a bad idea so that has to be reworked. All-in-all, the first spin of the board is working about as well as I had hoped. I’m also going to switch to larger buttons for the keypad.
There is no estimate on availability yet. It will definitely turn into a product but I’m really working hard to make sure it’s as close to perfect as possible, and that’s taking time.
I’ll try not to do several posts in one day but figured this was worth a mention. I have the KIM monitor running on the serial port, but with some changes to be in upper EEPROM and other minor mods. As testing continues, more errors are becoming apparent and I’ve done a number of cuts/jumpers to solve issues. It’s been a long day of testing and debugging so I will probably just take a break for the evening and get back to it tomorrow.
It looks like a new spin of boards will be ordered early next week with fixes to all the problems found so far. I will continue doing more debugging in the next few days, but it’s time for a clean board. So far, this is coming up a lot faster than I had planned.
My full time job and full time family keep me pretty busy but usually I can squeeze in at least an hour of quality time at the workbench most evenings.
As of this morning, the USB serial port is working, as are the two 6532 RIOT chips. The photo shows the Clone as it’s currently sitting on my workbench. When the USB cable is plugged in, the computer recognizes it and when typing characters the RC LED blinks. The USB serial chip is an FTDI device bought from a good distributor, so there should be no problems with drivers on any major OS.
For those not completely sure what this is about, the original KIM had a 20 ma current loop interface designed for mechanical teletype machines. Nobody uses 20 ma loops anymore, so Corsham’s KIM-1 I/O board coverts it to RS-232 using a standard 9 pin serial cable. Technology continues to evolve, and most computers don’t have RS-232 ports anymore, so this board has a chip that plugs into the USB port on your computer and is recognized as a COM port. The interface chip is powered from the USB cable (ie, your computer) so it doesn’t go away when you turn off the KIM Clone.
There is enough running now that the next step might be to install the KIM monitor EPROM and see if the system comes up using the serial port. As you can see from the pictures the keypad and LEDs aren’t installed yet so the TTY is the only debug option.