TLC5916 I/f with 89c2051

.6646.TLC5927 Application Source Code.rtf

Vivek,

(A.) In most applications the best way to adjust LED intensity is through Pulse Width Modulation, but

you may also change the gain for the LED drivers by writing a new gain code to them through their SDI pin.

I've attached some sample code for TLC5927 LED drivers which will help you in understanding the logic for

your application since these drivers are very similar to the ones you are inquiring about.  (Main difference is

more channels).

.

The code is written in C and is for the MSP430G2553 (MCU).  You can uncomment code in the main function to

write gain codes, but if you do this make sure to comment out the pwm_config function in main().

(B.) In most applications it is preferable to use more than one LED driver.  If you have 8 RGB LED chips

then I would recommend using 3 TLC5916 driver chips.  In most cases you want to have each driver control LEDs

that are of the same color  (one driver for red, one for green, and one for blue).

The reason you may want this is because R-EXT can be set up in facilitating color matching.

The code I provided assumes you have three TLC5927 LED drivers (one for each color led) and that the drivers are

communicating in an SPI daisy chain configuration.

(C.)I'm not sure how utilizing multiple TLC5916s will allow you to utilize high power LEDs.  Do you mean multiple LED strings?

If you mean to use multiple channels to handle high current for a single LED/ LEDs in series, then this is a dangerous configuration.  

Slight differences in channel output times can damage the drivers

PS:  Attached File best opens with WordPad.

Roberto Mancera

Thanks for the guidance and your effort.

I am studying the "c" code. My "c" programming is weak. Any 8051 ALP code possible ? (!)

I want to control a set of 8 RGB LEDs and vary the intensity of each LED (of 24 LEDs - 8RGB set each of 3 R-G-B LED) using 89c2051 MCU.

As per your suggestion I can use 3 TLC5916. 

Can you please suggest the connections and the algorithm for a 8051 based design ?

Thanks and regards

Vivek Ghosh

India

Hello Roberto,

If you could send a schematic of how you are connecting the LEDs and the MCUs, it would be helpful.

In general TLC5916 is controlled by one MCU driving the pins SDI, CLK, LE and /OE. For normal operation please check Figure 8 on page 14 in the datasheet.

Best regards,
Brigitte

Roberto Mancera

Thanks for the reply.

As I have already stated, I want to control a set of 8 RGB LEDs and vary the intensity of each LED (of 24 LEDs - 8RGB set each of 3 R-G-B LED) using 89c2051 MCU.

Can you please suggest the ALGORITHM for a 8051 based design ? I want to control the INTENSITY of each LED, the data for the intensity is transmitted by the MCU (I am using 89c2051 - 8bit  with 2kb Memory . I am using this as I have the burner which supports this low-cost MCU ! )

Awaiting your early responce,

Thanks and regards

Vivek Ghosh

India