7 Feb
2016
7 Feb
'16
1:13 p.m.
On 2016-Feb-07, at 6:17 AM, Robo58 wrote:
c). I hand assembled some code to exercise the 6850.
I know it has a
software reset and then you set attributes. I tried my buddies echo
program. It looks for a received character and then echo's it. I'm using a
laptop and PuTTy along with an RS-232 breakout box. I can see characters
going in but nothing coming out. The 6850 appears to drive the bus for a
finite amount of time and then turn off its drivers. I don't have any
experience with the part and I don't know if that's the way it's supposed to
work or that the Altair has a bus timing issue.
How about doing a program that simply repeatedly outputs a character first, getting that
going before trying to deal with input - cuts the problem space in half.
The repeat loop should give you some consistent bus activity and observable waveforms on a
scope if you have one, rather than trying to catch events initiated from external input
activity.