blittled
Member
I have been entertaining the thought of using a Teensy 3.5 as a replacement for the custom ULA IC found in the ZX81 computer. The ZX81 used the control lines of the Z80 to do the video generation rather than using a dedicated video chip. This requires constant monitoring of these lines.
I feel the best approach is to use an interrupt at each clock pulse and get the state of the control lines and address bus and save them to act on them in a main processing loop. With a 3.25 MHz Z80 clock my concern is locking up the Teensy. using most of its time in the interrupt routine. Also I would probably need to use assembly code to optimize routines for time.
Is this feasible or is there another approach that is fast enough to handle it? Thanks.
I feel the best approach is to use an interrupt at each clock pulse and get the state of the control lines and address bus and save them to act on them in a main processing loop. With a 3.25 MHz Z80 clock my concern is locking up the Teensy. using most of its time in the interrupt routine. Also I would probably need to use assembly code to optimize routines for time.
Is this feasible or is there another approach that is fast enough to handle it? Thanks.