Similar to the 8-bit external pattern mode, the maximum supported 24-bit input frame for 1-bit external pattern mode is 104.2Hz. In 1-bit pattern mode, each of the 24-bit inputs is treated as a separate binary pattern, resulting in a maximum of 24 patterns. The maximum pattern rate for each 1-bit pattern is 2500Hz.
The DLPC3478 controller firmware allows for the following user programmability:
- Exposure time: Time during which a pattern is displayed.
- Dark time: Time during which no pattern is displayed and the illumination is off.
- Number of 1-bit patterns within a frame - up to a maximum of 24.
- Illuminator: Illuminator that is on for each 1-bit pattern. User-defined illuminator is auto-selected for all the patterns within a frame. The user cannot select a different illuminator for different 1-bit patterns within a frame.
- TRIG_OUT_1 and TRIG_OUT_2 signal configuration and delay.
Figure 6-11 shows a configuration with 24 × 1-bit patterns.
- 24 × 1-bit patterns are displayed within each input VSYNC frame period.
- tDarkPre, tExposure, and tDarkPost are the same for each pattern within a frame period.
- The sum of dark time and exposure time (tDarkPre + tExposure + tDarkPost) for all the 1-bit patterns must be equal to or less than the full frame period. If the sum is less than the full frame period, additional dark time will be appended to the end of the last pattern.
- The Blue LED is configured to be ON for each pattern.
- TRIG_OUT_1 (Frame Trigger) is configured active high polarity and will have a minimum pulse width of 20 microseconds. TRIG_OUT_1 delay (tD1) is configured with respect to input VSYNC.
- TRIG_OUT_2 (Pattern Trigger) is configured active high polarity and stays active during the pattern exposure. TRIG_OUT_2 delay (tD2) is configured with reference to the start of the pattern and is set once per pattern within a frame.