With the Fantastic Chip Shortage however delaying deliveries of new factors, now may possibly be a good time to look all over your lab and inspect these piles of chips that you imagined “might arrive in helpful a single day”. Chances are you are going to find a great stack of 74xx sequence logic, when ubiquitous but today generally obsolete thanks to strong microcontrollers and FPGAs. It would be a disgrace to enable them go to squander, so why not use them to make a neat 1980s-design laptop?
With this idea in thoughts, [Anders Nielsen] designed the ABN6502: a one-board laptop based mostly on the venerable 6502 processor, but with fairly modern interfaces like a VGA monitor output, a PS/2 keyboard connector and even a wi-fi module to simplify firmware uploads from a Laptop. One style requirement was to lessen the range of new parts needed the regular hacker interested in making the ABN6502 will most likely have lots of of the chips lying about someplace in their workshop.
The component listing reads like a typical monthly bill of products for a 6502-centered computer, but will come with a large amount of versatility to let for portion subsititution. For the CPU, both of those the common NMOS 6502 as well as the present day CMOS-based 65C02 are supported, along with their 6522 companion chip that provides I/O ports and timers. A ROM socket can keep both modern day, quickly flash chips or standard but sluggish UV-erasable EPROMs.
As a substitute of applying DRAM chips with their difficult refresh necessities, [Anders] went for 32 KB of SRAM to put into practice the principal memory unaffordable in the ’80s but very easily accessible currently. Conventional 74xx collection logic chips glue all the factors with each other, once more with several solutions to increase or clear away attributes as the person prefers. Pin headers convey out the I/O ports for simple link to external peripherals.
The ABN6502’s software program library is now restricted to a bootloader, but a entire growth toolchain based mostly on the CC65 compiler really should make it quick to create all kinds of applications on this platform. We have now featured the intelligent wi-fi ROM flashing system, as well as a demonstration of the 6502 driving RGB LEDs.