Spock's operation is defined by the Option Byte R7 which has 6 control bits:

Bit	Name	Value	Meaning
5	Trigger Type	0	Trigger operation is Level Sensitive.
		1	Trigger operation is Edge Sensitive.
4	Edge Direction	0	Trigger asserted on FALSE -> TRUE
		1	Trigger asserted on TRUE -> FALSE
3	Page Selection	0	Lower 16K RAM Page and Analog BNC Input.
		1	Upper 16K RAM Page and Analog POD Input.
2/1	Trig Bit 7 MUX	0	DD7 : Digital Data Bus Bit 7.
		1	Comparator : trigger match comparator signal.
		2	Event 1 : (Pre-scaler output frequency halved).
		3	Event 2 : (ADC input frequency halved).
0	Trigger Source	0	Digital trigger source.
		1	Analog trigger source.

Bits 6 and 7 are reserved and should be programmed with zero for compatibility with future Spock revisions. All these bits must be programmed before each data capture trace.

The following pages describe these bits and other Spock registers in more detail.