Re: [EE] New retro-computing project

On 10 Mar 2026 at 15:42, Harold Hallikainen wrote:

> One thing I really like about microcontrollers is that the address and
> data buses stay inside the chip. With systems with external memory and
> I/O, it is a real pain to find a problem when it affects one of the buses
> since NOTHING works. With microcontrollers, I can put in a power on self
> test that tests all the external devices and lets me know they are
> working.

I remember looking for such problems... drop in an EPROM filled with NOPs (0x00 
for 8051), or maybe a resistor network pulling the 8 x data lines low, scope the 
address lines to see a nice square wave on each, halving in frequency as you step 
up to the next address bit.