[Coco] PIA keyboard input?

[James Dessart]

I'm trying to figure out how to read the keyboard from the PIA, and 
I've checked out BASIC Unravelled.  What it seems to be is that you 
place a 0 into the bit of the column strobe that you want, and then 
check the rows to see if there are keys depressed in that row.  Is that 
correct?

So, as I see it, to find out which keys are depressed, I need to roll a 
0 through the column register, and check the row register.  Depending 
on which I see depressed, I can say which keys are pressed.  Do I have 
a good understanding of this?  Other than the joystick button bit, are 
there any caveats to this?

James