I have a project in which I must drive 4 RGB LEDs using PWM directly from the MSP430. They are separated in two groups of 2 LEDs (1 PWM connection controls one color element of two LEDs) which means I have 6 PWM connections to my uC (two for each color R, G or B). My uC is a MSP430F5438, having a Timer B with 6 CCRs, therefore able to provide 6 PWM hardware signals.
(sorry for the horrible sketch)
They must light all with the same color, possibly blinking with 1 second frequency or so. My question is: how could I save as much power as possible managing/multiplexing the PWM signals and the two groups of LEDs? I thought about simple PWMs for all the 6 signals, or also using only 3 PWMs and multiplexing between the two groups. I'm willing to use software ISR but I only have timer B available for that (to use together with the PWM). Should also be a quick operation due to the rest of the program being relatively heavy. The use of a LED driver is out of question. Thanks.