If only one write was made to $2006, thus specifying only its high byte, what address should be used when reading or writing to $2007?
1) The address low byte should be 0
2a) The address low byte should be all screwed up from last render which used it for internal tasks
2b) The address low byte remains the same as the last time it was set by a second write to $2006 (provided no render happened in between)
In the same sense, what vertical scrolling should be used if only one write was issued to $2005 and the time comes to begin (or continue) rendering?
1) The address low byte should be 0
2a) The address low byte should be all screwed up from last render which used it for internal tasks
2b) The address low byte remains the same as the last time it was set by a second write to $2006 (provided no render happened in between)
In the same sense, what vertical scrolling should be used if only one write was issued to $2005 and the time comes to begin (or continue) rendering?