pattern sequence problem

Hi Di,

At present (as on software update DLPLightCrafter_FW_SW_v1.1_2012_07_19) the Pattern Sequence in AUTO trigger mode has following max exposure capability -

2-bit to 8-bit pattern sequence <= 5.1Seconds

1-bit pattern sequence <= 2.0 Seconds

So, for your specific requirement (1-bit 400-600 patterns with display time interval of 10 Seconds) there are two ways to acheive this

1) Command Mode : Procedure, Select 'N' number of 1-bit patterns, Set Exposure = 0.0, upload ALL the patterns, start the pattern sequence, now in your PC side application wait for say 9.7seconds and then issue command to display 'next' pattern in the sequence. Pros - Simple and easy to use. Cons - Will not yield precise timing and additional PC side software application dependency.

2) External Trigger Mode: Procedure, Select 'N' number of 1-bit patterns, Set Exposure = 0.0, upload ALL the patterns, start the pattern sequence, now send 10.0 periodic triggers of 10.0Seconds to display patterns. Pros - Precise timing Cons - Additional Hardware for 10.0 trigger generation.

Let me know the MSP430 SW version you are using?

Regards,

Sanjeev

Thanks Sanjeev,

You mean the "Command Mode " and "External Trigger Mode"  under "Input Trigger" Selection? There are two External Trigger Mode (positiv and negativ).

When i set into "External Input Trigger", and  select 'N' number of 1-bit patterns by "Image file" , there are no image to project.

And for these 2 Mode, there are still only max. 96 images can be projected.

My MSP430 version: 2.5

thanks,

regards,

Di

Hi Di,

GUI v3.8 has Pattern Count box is both drop down and editable. Drop-down list show 96 but you can enter directly the number like 400.

Regards,

Sanjeev

Thanks dear Sanjeev,

As you said, by External Trigger Mode we need an additional Hardware for 3.0~10.0 trigger generation, can you please tell me which time-trigger i should get or buy?

regards,

Di

Hi Sanjeev,

I was able to upload more than 96 1-bit images by the drop down list trick. However, I was not able to have LCr display all the images using either Command or Auto trigger. It pops up a COMMAND FAILED window everytime unless I change the number in drop down list back to 96 or lower. ANy ideas? Thanks!

Hi Rong Sun,

This is important message I think we missed to put in the new release README file.

As you know the new f/w upgrade available for LightCrfater here http://www.ti.com/tool/dlplightcrafter v1.1. This package has DM365 f/w upgrade version 3.31. For those who all plan to use Extended Pattern Setting or plan to use more than 96 patterns. Please check for minor hardware modification on the System Board.

Here is the change:

On System Board, there is resistor place holder R205. For the LightCrafter kits on which this resistor is not populated you will have to install a 0 Ohm resistor to use the extended pattern mode. The board which already has this resistor populated there is NO change needed.

Let me know if you are still facing the problem even after doing the hardware change.

Regards,

Sanjeev

Sanjeev said:

Hi Rong Sun,

This is important message I think we missed to put in the new release README file.

As you know the new f/w upgrade available for LightCrfater here http://www.ti.com/tool/dlplightcrafter v1.1. This package has DM365 f/w upgrade version 3.31. For those who all plan to use Extended Pattern Setting or plan to use more than 96 patterns. Please check for minor hardware modification on the System Board.

Here is the change:

On System Board, there is resistor place holder R205. For the LightCrafter kits on which this resistor is not populated you will have to install a 0 Ohm resistor to use the extended pattern mode. The board which already has this resistor populated there is NO change needed.

Let me know if you are still facing the problem even after doing the hardware change.

Regards,

Sanjeev

Hi Sanjeev,

It worked. I soldered a wire on R205 and it now allows me to display more than 96 images.

However, the frame rate I can achieve seems to stuck around 60 Hz. Here is my setting:

Trigger type: auto

expose time: 0 (on for the duration of one period)

trigger time: any number, e.g. 2500 usec (400Hz) or 0 sec ( I would assume it will go as fast as it can when trigger time is set to 0 usec.)

unchecked all check-boxes.

The actual frame rate I measured using oscilloscope is ~60 Hz.

Please give me your thoughts on how to control the frame rate in Pattern mode.

Hi Ron Sun,

What you are doing is correct. And the ~60Hz frame rate you are reading is also correct.

For extended pattern mode (i.e., more than 96 patterns) there is limitation on minimum trigger period. You will notice that when you set 0 (ZERO) exposure time the trigger period defaults to 18000uSec on read back. What it means is that for more than 96 patterns the maximum refresh rate possible decreases to ~60Hz i.e., 55.55Hz.

So, for extended pattern mode the minimum trigger period is 18000uSec (18mSec) or 55.55 frame per second. This is the system limitation and it is not possible to go higher frame rate than this.

Regards,

Sanjeev

Sanjeev said:

Hi Ron Sun,

What you are doing is correct. And the ~60Hz frame rate you are reading is also correct.

For extended pattern mode (i.e., more than 96 patterns) there is limitation on minimum trigger period. You will notice that when you set 0 (ZERO) exposure time the trigger period defaults to 18000uSec on read back. What it means is that for more than 96 patterns the maximum refresh rate possible decreases to ~60Hz i.e., 55.55Hz.

So, for extended pattern mode the minimum trigger period is 18000uSec (18mSec) or 55.55 frame per second. This is the system limitation and it is not possible to go higher frame rate than this.

Regards,

Sanjeev

55.5 Hz is exactly what I measured. It's good to be able to confirm that.

Now, what's the option for me to go above this frequency barrier? I can use the HDMI video mode. However, the refresh rate is capped at 60 Hz for 8-bit RGB video. Is this 60 Hz something can be changed?

Thanks,

Hi Ron Sun,

Yes, with external pattern sequence you will be able to achieve higher frame rate. Basically here you will have to configure HDMI video to be interpreted as pattern data. For 8bit patterns a single video frame can accomdate 2 8bit patterns. So in one RGB888 24bit frame the R8 and G8 are consider as two 8bit patterns that will be displayed on the DMD.

The configuration for this would be -

Display Mode = HDMI Video Input

Video Mode Setting = Bit Depth - 8bit, Frame Rate = 60Hz, LED Select = Red or Green or Blue (NOT RGB)

As explained above, 1 RGB888 24bit frame can accomdate two 8bit patterns, so effectively possible pattern rate at 60Hz will be 60 x 2 = 120Hz.

From information on this configuration refer to DLPC300 programmer's guide http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=dlpu004&fileType=pdf section 2.3.1.1.2.4 8-bit Monochrome External Video

Regards,

Sanjeev

Sanjeev said:

Hi Ron Sun,

Yes, with external pattern sequence you will be able to achieve higher frame rate. Basically here you will have to configure HDMI video to be interpreted as pattern data. For 8bit patterns a single video frame can accomdate 2 8bit patterns. So in one RGB888 24bit frame the R8 and G8 are consider as two 8bit patterns that will be displayed on the DMD.

The configuration for this would be -

Display Mode = HDMI Video Input

Video Mode Setting = Bit Depth - 8bit, Frame Rate = 60Hz, LED Select = Red or Green or Blue (NOT RGB)

As explained above, 1 RGB888 24bit frame can accomdate two 8bit patterns, so effectively possible pattern rate at 60Hz will be 60 x 2 = 120Hz.

From information on this configuration refer to DLPC300 programmer's guide http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=dlpu004&fileType=pdf section 2.3.1.1.2.4 8-bit Monochrome External Video

Regards,

Sanjeev

Hi Sanjeev,

What would be the max. refresh rate for displaying more than 96 images in pattern mode if I were to use external trigger instead of auto?

Thanks,

Rong

Hi Rong,

For more >96 patterns in pattermode it is same as AUTO mode sequence. So, it is limited to maximum of 55Hz refresh rate.

Regards,
Sanjeev