In Xiphod’s latest video, viewers get an insightful look into using an RS-232 Keyboard Interface for a Commander X16. The demonstration involves writing code to utilize an RS-232 interface instead of a traditional system keyboard. For this setup, a Tandy Model 102 acts as the keyboard, connecting via an RS-232 null-modem cable to the Commander X16’s serial card interface.
The coding process is straightforward, employing BASLOAD—a native X16 utility. BASLOAD converts plain-text BASIC, which lacks line numbers, into standard CBM BASIC. Although Xiphod uses BASIC, programmers can easily adapt these core coding principles to other languages as well.
To achieve seamless operation, the software utilizes an Interrupt Service Routine (ISR) running alongside the main system kernel. Enhancing the visual clarity, SEMIBIGFONT was initially selected to display the ASCII characters. However, Xiphod later decided to send inputs directly to the kernel. This allows remote system operation, provided the invoked programs don’t heavily depend on the Golden RAM region.
To avoid potential memory conflicts, Xiphod suggests relocating the ISR to banked memory. Alternatively, a simpler solution involves adjusting BASIC’s MEMTOP, placing the ISR handler safely above the Golden RAM region.
The Commander X16 showcased in the video is the impressive “Carbon Fiber” Developer Edition PR900. This custom-built system boasts over 10 hours of battery life, a 12-inch VGA LCD screen, built-in speakers, four SNES ports, an IEC-emulated disk drive, and a handy USB charging port. Nearby sits the X16 #PR16 in a distinctive blue case from Bit by Bit Synths, running Tony’s renowned SLIDESHOW program.
Anyone interested in exploring this setup further can find Xiphod’s detailed code on the Commander X16 forum.
