I've read some of the data sheet for the TLC 5940 and it states the following about the BLANK input:
Blank all outputs. When BLANK = H, all OUTn outputs are forced OFF. GS counter is also reset. When BLANK = L, OUTn are controlled by grayscale PWM control.
Looking at this image:
... from the Arduino playground about using the TLC chip with Arduino it shows a 10k pull-up resistor to reset the chips when the device is turned on.
I read about pull-up resistors so I get that when power is supplied the resistor allows BLANK to read a high input. What I don't get though is how the chip works after that. I don't see anything that sets BLANK to low.
How is the BLANK input getting set to LOW so the device can operate normally?