How to display dot on 7-seg , 4 digit

[paul borgmeier]

I see - the PNPs (which I did not know about) threw me off. It appears proper for Common Anode.

Try this:
1) On your buffer, tie 1 and 19 low so they do not float.
2) The 3rd from last line of your code - change "Return" to "Resume" (See manual section on On Interrupt for details).

Please report back progress so that others following this can get closure.

EDIT:
3) Your lookup values need to be inverted - as written they are for common cathode displays. Change to ($C0, $F9, $A4, etc) where the segments you want off are high and the segments you want on are low.
4) To turn on the decimal point on the second digit, insert right after the lookup table
if i = 1 then Segments.7 = 0 (or if the DP is always to be on you could do this in hardware by disconnecting RC7 from D7 on U2 and connecting RD1 to D7 on U2 (in addition to RD1 going to the Base of Q2))