Talk:Hero/@comment-24.27.45.172-20150615113040

how old is this post? The paper you cited was great for a *nix system and some of those parts are getting difficult to find. It does work FWIW. Replacing cranky ol 6808 (or variant) motherboard with a nice Arduino MEGA and keeping the i/o boardis a better paththan tapping headers on cpu board. IMO. Place the 6808 in a nice display box. Originally et18 bit banged a serial port off the proto on top and used 1488_9 for 232 levels. You say u have schematics and verifying what you've written shouldn't be a problem so I am a bit puzzled as to your intent.

Overall the et18 had 8 input and 8 output ports and a few interrupts. The majority i/o go to io board. All 8 bit paths and latched on i/o.

somethings you may need to know:

original battery charging circuit sucks. 7812s can be adjusted to a more reasonable 13.8V-14.2. Otherwise expect quickly declining battery life. Good temporary fix anyway. The battery low voltage detect circuit is easily tripped on loading. As this creates an interrupt  Draw your own conclusion there.

switching regulator is set too high at 5.5vdc which was at the top range for ttl. More modern circuits wont like that. consider bringing down to 5.1 max.

sonar uses 32-38khz rtc clock and interrupt.

ye old 256 phoneme synth board  is about the easiest hookup. it does use the two extra bits to control amplitude.

I could rant on.

I haven't posted my mods for the same reason you haven't:. Copyright troll.

I believe HERO ET(W)-18 has great untapped potential if not for anything more than inspiration but still a good teaching tool. I've seen too many stuffed in storage where there potential is short circuited.

today is Monday June 15, 2015.

I'll check back later for comments