DLPC3470: dlpc3470 Splash Pattern 模式为什么会设置最大 Pattern 周期，这个最大周期能否更改？

dlpc3470 Splash Pattern 模式为什么会设置最大 Pattern 周期，这个最大周期能否更改？

Sophie Chen：

你说的是light control模式，为了针对3D 打印和3D扫描的一种模式，这个模式下，图片是有曝光周期的，然后有触发信号触发工业相机等外围设备。如果只是想显示一个splash图片可以直接使用display模式或者DLPC3430芯片。具体参考datasheet和programmer guide.

,

user6411851：

这个应用上是需要触发工业相机，但是针对高分辨率的卷帘相机，帧率比较低，限制最大曝光周期相当于限制了最小帧率，这样搞导致无法正确的触发相机，从而导致图像出现错误。虽然Spalsh 模式确实只是起到显示作用，但是是希望这种显示能够通过相机进行观察。不清楚设置最大触发周期的意义是什么，这个能否进行更改？

,

user6411851：

,

Jeremy_Wu：

参考固件说明：

https://software-dl.ti.com/dlp/pico-fw-selector/release_notes/FWSel_DLPC3478_DLPA2005_pm1_i2c0x36_v8p0p1.html

Texas Instruments

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DLPC3478 Firmware v8.0.1 Release Notes
March 14, 2022
Table of Contents

Overview
Supported Features
Updates in this release
Known Limitations
Technical Support and Product Updates

Overview

These are the release notes for the following firmware image file:

Firmware Version: 8.0.1
Embedded Software Version: 8.1.0
Generated from DLP Composer Version: 13.13

DMD: DLP3010LC
Controller: DLPC3478
PMIC: DLPA2005

Configuration Settings

I2C Address: 0x36
DMD Pin Mapping: 1
Rlim value: 39mΩ
Light Control Sequence Database Version: 0.5.71

Supported Features

Light Control
Internal Pattern Streaming Mode: – Trigger-In/Free-running modes (Mono 1 Bit/8 Bit, RGB 1 Bit/8 Bit, Vertical + Horizontal Pattern Generation, Pattern Invert)
External Pattern Streaming Mode (Mono 1 Bit/8Bit, RGB 1 Bit/8Bit)
Zero dark time external pattern display for illumination time less than 400 uSec
Splash Patterns (Mono 1 Bit/ 8 Bit)

Display
External video input
IntelliBright video processing algorithms
Splash Screens
Source frame rates supported – 0 to 123 HZ
Four 2D looks (cool, medium, warm, and other) and one 3D look

Supported pattern timings in Sequence Database v0.5.71:

Internal Pattern Mode Timings:

Pattern Type
Sequence Index
Exposure Time Range (us)
Sequence Min Pre-Exposure Dark Time (us)
Sequence Min Post-Exposure Dark Time (us)

1-bit Monochrome
18
200 – 399
171
31

17
400 – 799
171
31

16
800 – 799
171
31

15
1800 – 3799
171
31

14
3800 – 7600
171
31

1-bit RGB
25
600 – 1799
171
31

24
1800 – 3799
171
31

23
3800 – 7600
171
31

8-bit Monochrome
20
3464 – 6928
171
31

21*
1677 – 3463
171
31

8-bit RGB
22
10912 – 21824
171
31

*Sequence 21 is a special sequence that displays 7-bit patterns. The least significant bit of the 8-bit pattern data will be ignored.

Notes:

For internal patterns, there will be an additional variable delay of ~3000 us at the beginning of every pattern set.
Exposure times shorter than the above values are not possible. Longer exposure times will operate with decreased timing accuracy and behavior is not guaranteed.
Shorter dark times are not possible. Longer dark times can be used. The maximum possible dark times for a desired exposure time are:

Tmax pre-exposure dark time  = ( 27306us + tsequence min pre-exposure dark time ) * (Tdesired exposure / tsequence minimum exposure)
Tmax post-exposure dark time = ( 27306us + tsequence min post-exposure dark time ) * (Tdesired exposure / tsequence minimum exposure)

External Pattern Streaming Timings:

Pattern Type
Sequence Index
Exposure Time Range (us)
Sequence Min Pre-Exposure Dark Time (us)
Sequence Min Post-Exposure Dark Time (us)

1-bit Monochrome
6
200 – 400
0*
0*

5
200 – 399
171
31

4
400 – 799
171
31

3
800 – 1799
171
31

2
1800 – 3799
171
31

1
3800 – 7600
171
31

1-bit RGB
11
451 – 799
171
31

10
800 – 1799
171
31

9
1800 – 3799
171
31

8
3800 – 7600
171
31

8-bit Monochrome
7
2555 – 5110
171
31

8-bit RGB
0
10912 – 21824
171
31

*Sequence 6 is a special sequence with zero pre-exposure and post-exposure dark times. (Note: While running this sequence, a dark time equivalent to the exposure time of one pattern will be added at the start of every pattern set.)

Notes:

Exposure times shorter than the above values are not possible. Longer exposure times will operate with decreased timing accuracy and behavior is not guaranteed.
Shorter dark times are not possible. Longer dark times can be used. The maximum possible dark times for a desired exposure time are:

Tmax pre-exposure dark time  = ( 6553us + tsequence min pre-exposure dark time ) * (Tdesired exposure / tsequence minimum exposure)
Tmax post-exposure dark time = ( 6553us + tsequence min post-exposure dark time ) * (Tdesired exposure / tsequence minimum exposure)

Splash Pattern Mode Timings:

Pattern Type
Sequence Index
Exposure Time Range (us)
Sequence Min Pre-Exposure Dark Time (us)
Sequence Min Post-Exposure Dark Time (us)

1 -bit Monochrome
13
793 – 1744
171
31

8-bit Monochrome
12
7737 – 17034
171
31

Notes:

The maximum pattern period (pre-exposure + exposure + post-exposure) cannot exceed 2184us for 1-bit splash patterns and 17476us for 8-bit splash patterns.

The listed minimum dark times are applicable for the minimum exposure time of each sequence. The dark times scale along with the exposure time as per the following equation:

Tmin required pre-exposure dark time  = tsequence min pre-exposure dark time * (Tdesired exposure / tsequence minimum exposure)
Tmin required post-exposure dark time = tsequence min post-exposure dark time * (Tdesired exposure / tsequence minimum exposure)

I2C command 0x9D (Read Validate Exposure Time) returns the minimum required pre-exposure and post-exposure dark times for a specific pattern type and given exposure time.

Updates in this release

Firmware will support the systems with the Light Control DMDs (DLP2010LC, DLP3010LC) only.
Auto-idle mode is not supported.
Only DMD pin mapping options 1 and 2 are supported.
The corruption observed in internal pattern mode while running 200us zero dark time pattern sets has been fixed.
Patterns are only supported in RGB format (not YCbCr) when running in Splash Pattern mode.
Thermistor processing enabled by default

Known Limitations

Internal Patterns 8 bit RGB sequence – post dark time does not match specified value.
Non uniformity is seen at the display borders while running 1 bit internal patterns with 0 pre,post exposure times.
External Streaming – Signals/Patterns Incorrect in case of VSYNC jitter.
When switching from internal pattern mode to splash pattern mode make sure that the internal pattern display is stopped.
While using the update firmware feature of GUI, make sure that size of splash image are as small as possible and prefer selecting RGB color space if the images are of PNG format.
LC splash pattern dispaly is only supported in RGB format.
Only RGB888 input source format supported in External Pattern Streaming Mode.
Unsupported Features:

DSI/BT656 Input
CPU Interface
LABB with Ambient Light Sensor support
Shallow Gradient
White Point Correction
I2C at 400KHz
Flashless configuration
Idle mode
Power management, clock gating and scaling
CAIC is not supported in LC, system will not boot up in LC mode with CAIC enabled

Technical Support and Product Updates

Thermistor Processing Documentation

Using System Temperature via I2C commands:
Read System Temperature (0xd6)
Output: 2 Bytes
Byte 1: LSB
Byte 2: MSB

Note: The temperature of the thermistor is read in degrees Celsius in a magnitude of 10 times the reading of thermistor. Bit 11 (the most significant bit) denotes the sign temperature. A '0' means a positive temperature, while '1' denotes a negative temperature.
Example #1: b(11:0) = 000110101010; 426d / 10d = 42.6degC
Example #2: b(11:0) = 100110101010; 426d / 10d = -42.6degC

Note: This temperature reading will need to be calibrated per the design and specific thermsitor chosen of custom boards. Offset to determine the true temperature of the thermistor reading. Texas Instruments DLP hardware uses Murata's NCP15WF104F03RC.

Additional Links

DLPC347x Software Programmer's Guide
DLP Products® E2E Forums
DLP Products® – Getting Started
DLP Pico Products overview
DLPC3470 Controller
DLP2010LC DMD
DLPC3478 Controller
DLP3010LC DMD

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