Tlc5940, by Alex Leone, interfaces with one of more TLC5940 chips from Texas Instruments. Though expensive, each chip provides 16 PWM outputs with 12 bit resolution, and built in current limiting for directly driving LEDs without resistors.

Download: Tlc5940.zip (version r014, with modification for Teensy)

Tlc5940 works on Teensy 2.0, Teensy++ 1.0, and Teensy++ 2.0. Teensy 1.0 is not supported.

Hardware Requirements

Tlc5940 test board. Wiring details shown below

The TLC5940 chip (PDF) requires only 2 resistors and connects to Teensy using 5 signals.

Signal	TLC5940 Pin	Teensy 2.0 Pin	Teensy++ 1.0 Pin	Teensy++ 2.0 Pin
GSCLK	18	9	1	1
BLANK^*	23	15	26	26
XLAT	24	14	25	25
SCLK	25	1	21	21
SIN	26	2	22	22
VPRG, GND	27, 22	Connect to GND
DCPRG, VCC	19, 21	Connect to +5V
IREF	20	Connect 2.2K resistor to GND
Must be output mode	-	0	20	20
Unusable as PWM	-	4	24, 27	24, 27

^* The BLANK pin should have a 10K resistor connected to +5V.

Several TLC5940 chips may be used. The SOUT signal (pin 17) of each connects to the SIN (pin 26) of the previous chip, and GSCLK, BLANK, XLAT, SCLK are connected in common to all chips.

Example Programs

Tlc5940 includes several examples, available from the File > Examples menu.

File > Examples > Tlc5940 > BasicUse

File > Examples > Tlc5940 > Fades

Peripherals Used

Tlc5940 uses the SPI port and 2 timers. The MISO pin is not used. The SS pin may only be used as an output. Timer1 and Timer2 are used on Teensy++. On Teensy, Timer1 and Timer3 are used. Some PWM pins associated with these timers are either used by the library. The others may be used as input or output, but not as PWM (analogWrite).

Wiring and Pinout Info

Details

For more details, please refer to the official Tlc5940 page, or this older page.