The LP5866 supports three data refresh modes: Mode 1, Mode 2, and Mode 3, by configuring 'Data_Ref_Mode' in Dev_initial register.

Mode 1: 8-bit PWM data without VSYNC command. Data is sent out for display instantly after received. With Mode 1, users can refresh the corresponding dot data, only instead of updating the whole SRAM. It is called ‘on demand data refresh’, which can save the total data volume effectively. As shown in Figure 7-7, the red LED dots can be refreshed after sending the corresponding data while the others kept the same with last frame.

Figure 7-7 On Demand Data Refresh – Mode 1

Mode 2: 8-bit PWM data with VSYNC command. Data is held and sent out simultaneously by frame after receiving the VSYNC command.

Mode 3: 16-bit PWM data with VSYNC command. Data is held and sent out simultaneously by frame after receiving the VSYNC command.

Frame control is implemented in Mode 2 and Mode 3. Instead of refreshing the output instantly after data is received (Mode 1), the device holds the data and refreshes the whole frame data by a fixed frame rate, f_VSYNC. Usually, 24Hz, 50Hz, 60Hz, 120Hz or even higher frame rate is selected to achieve vivid animation effects. Whole SRAM Data Refresh is shown in Figure 7-8, a new frame is updated after receiving the VSYNC command.

Figure 7-8 Whole SRAM Data Refresh

Comparing with Mode 1, Mode 2 and Mode 3 provide a better synchronization when multiple LP5866 devices used together. A high-level pulse width longer than t_{SYNC_H} is required at the beginning of each VSYNC frame. Figure 7-9 shows the VSYNC connections and Figure 7-10 shows the timing requirements.

Figure 7-9 Multiple Devices Sync

Figure 7-10 VSYNC Timing