im running a system that needs to be able to send and receive data in a daisy chain to output Nine(3 in P, 3 in S), 700mA x3.8vf "RGBAW" leds each unit. I am planning to use an FQP30N06L FET to switch the 12V power. the micro controler needs to be able to receive data from a main board and flash accordingly and in the correct colour and tell the other units what to do as well. each unit in a line needs to be able to operate by its self or as a grouping (group A or group B). ideas?
The ATTiny841 seems to fit this application like a glove - 6 PWM channels so you can drive all the channels (that's 5 right?), and two serial ports, so you could have it take commands on one, and pass the command down the chain on the other (and likewise with return responses)....
What are you using to do the constant current regulation? (I generally reach for AMC7140's here - and I happen to sell breakout boards for them too) You're better off with one current regulator for each series string, unless you have faith that the LEDs are uniform enough that the current will end up being distributed fairly evenly.
will definitely consider integrating a current regulator and that ATTiny841 sounds great! is it a standalone or does it need anything to run with it ? can it be programmed just by the 2 pins or does it need a usb serial style like the arduino? basically im desiging a produce that uses RGBWA leds and you can plug one into another or attach them like lego brick and have pins contact pads to carry power and TX/RX. im planning on using an ethernet style jack for txrx and an XT-60 for power.
They can be loaded with the Optiboot bootloader, and programmed via serial (they don't have native USB, so you still need a serial adapter), or programmed via ISP like any other AVR microcontroller.
So if I'm sending with a serial say though a 8 pin eithernet jack I could use that ? Don't nesassarly need USB actually prefer not to. But I'm also not familiar with programming any micro controller other then arduino though USB with the arduino programming tool.
He much is just the controler?
Yeah - over at least short distances, serial via an ethernet jack is no problem. Bring out the DTR pin too so you can auto-reset the chip to make it easy to upload to.
The tiny841 bare chip? From the usual suspects, just under $2 in small quantities, just under $1 in large quantities.