control LED intensity with matlab

Hello Fred,

Per interface LightCrafter DM365 command interface document specification, LED Current Setting (0x01 0x04), the payload is 6-bytes, 2-bytes each for Red, Green and Blue LEDs, 

Let us know if you are looking for something else? 

Regards,

Sanjeev

Hi Sanjeev,

thank you very much for the quick answer!

I am still a bit confused about the format of the header.

here is the matlab code that I use. Is the format of the header/payload correct? What is the format of the bytes to modulate the intensity? Sorry I am new at programming!

tcpObject = tcpip('192.168.1.100',21845);

fopen(tcpObject);

obj = LightCrafter();

header = obj.createHeader();

header( 1 ) = uint8( hex2dec( '02' ) ); %packet type

header( 2 ) = uint8( hex2dec( '01' ) ); %CMD1

header( 3 ) = uint8( hex2dec( '04' ) ); %CMD2

header( 4 ) = uint8( hex2dec( '00' ) ); %flags

header( 5 ) = uint8( hex2dec( '00' ) ); %payloadLength LSB

header( 6 ) = uint8( hex2dec( '00' ) ); %payloadLength MSB

payload = uint8( [ hex2dec( '0' ) ; hex2dec( '0' ); hex2dec( '0' );hex2dec( '0' ) ; hex2dec( '0' ); hex2dec( '0' )] ); 

packet = obj.appendChecksum( [ header; payload ] );

 obj.sendData( packet, tcpObject );

Hi,

I quickly glanced at Jan's git https://github.com/fglichttechnik/TI-DLP-LightCrafter

I appears to me you are not properly updating the payload length i.e.,

header(5) & header(6), change your code to 

header( 5 ) = uint8( hex2dec( '06' ) ); %payloadLength LSB

header( 6 ) = uint8( hex2dec( '00' ) ); %payloadLength MSB

It should work I think.

Regards,

Sanjeev

Thanks a lot, it works just fine!

However I am still confused about the format of the header to specify individual LED intensities :

why are there 2 bytes per LED? One should make it just fine in principle?

Specifically, how do you set different intensity levels from 0 to the maximum one?

Thanks a lot

Hello Fred,

why are there 2 bytes per LED? One should make it just fine in principle?

[Sanjeev]

The DLPC300 register exposes it as a 10-bit register setting, so the digital LED current PWM values are set b/w 0 - 1023. Note, the register definition, 1023 - setting is for minimum and 0 - setting is for maximum.

Where as in the DLP LightCrafter DM365 command interface guide, that you are using currently, is inverted to look normal, that is 0 - minimum and 1023 - maximum current. 

Specifically, how do you set different intensity levels from 0 to the maximum one?

[Sanjeev] Since you are communicating to DM365 on the Kit, you should follow the minimum - 0 and max - 1023 approach. Different intensity levels, you can write any values 0x000 to 0x400.

Note sure i have answered your question completely, let us know if anything not clear here.

Regards,

Sanjeev

Thanks Sanjeev,

I am still a bit confused.

To be more precise, I use that kind of payload (this one turns all the LED off) :

0

0

0

0

0

0

each pair of  two consecutive bytes corresponds to one LED (redfirst then green then blue).

I still do not get how do you map the 1024 levels to values between 0x000 and 0x400 (by the way I do not undestand neither your conventions : what are the numbers before and after the x symbol?)

Pratically, I think I would understand with an exemple :How would you write the payload associated to full power on the red, and an intermediate level on the red, like 500?

Thanks again!

Fred

Hello Fred,

x stands for hex number representation. Each LED current takes two-byte of data, so the min and max will be 0x0000 to 0x0400 (Referring to LightCrafter DM365 Command Interface document)

Example: Red LED max - 200, Green -  400, Blue - 1023 in hex representation it will be 0x00C8 , 0x0190, 0x0400 respectively. 

The payload looks like

0xC8

0x00

0x90

0x01

0x00

0x04

Let me know if it helps.

Regards,
Sanjeev

thanks a lot Sanjeev,
it works perfectly!