26
3�4�3 Analog Trigger
You can choose either CH0, CH1, CH2 or CH3 as the trigger signal while using external
analog trigger source. The trigger level can be set by software with 8-bit resolution. Please
refer to Table 3-3 for the ideal transfer characteristic.
Trigger Level Setting (Hex)
Trigger Voltage (-1V to +1V
Range)
Trigger Voltage (-0�2V to
+0�2V)
0xFF
0.992V
0.1984V
0xFE
0.984V
0.1968V
---
---
---
0x81
0.0078V
1.56mV
0x80
0V
0V
0x7F
-0.0078V
-1.56mV
---
---
---
0x01
-0.992V
-0.1984V
Table 3-3: Ideal Transfer Characteristics for Analog Triggers
The trigger conditions for analog triggers are illustrated in Figure 3-9 and described as
follows:
• Positive-slope trigger: The trigger event occurs when the trigger signal (analog input
signal) changes from a voltage that is lower than the specified trigger level to a
voltage that is higher than the specified trigger level.
• Negative-slope trigger: The trigger event occurs when the trigger signal (analog input
signal) changes from a voltage that is higher than the specified trigger level to a
voltage that is lower than the specified trigger level.
Trigger Level
Positive-Slope Trigger Event
Occurs
Negative-Slope Trigger
Event Occurs
Analog
Signal
Figure 3-9: Analog Trigger Conditions