Hi, ive been using the tlc 5940 and was wondering if there was a good ic to just expand the number of pwm out put's in the same way using spi. Ive found this Cytron.io - Simplifying Digital Making
But was wondering if there was something already in use with library's for the arduino. i would want to daisy chain them as you can the tlc 5940, i dont know if the MP08A let's you do this.
any ideas?
I don't think that can be daisy-chained in the way you'd like. You can run them on a common SPI bus so long as each chip has a separate Slave Select (SS) signal.
I2C busses assume each chip has a different function byte I think.
I've seen LED driver PWM chips that can be daisy-chained (WS2801 for instance), but they have current-controlled outputs which might not be what you want.
The ws2801 is great, simple wiring and a super easy two wire serial deal. Plus its super cheap, I'm trying to get a board manufactured using it to control some high powered LEDs. If your interested check out my shift register LED board thread
... any ideas?
The AtMega168/AtMega328P will give you 6 PWM's plus choice of serial, SPI or I2C interface.
Yep all fine ideas. But i don't need constant currant it would be easier if it wasn't there ( this is for driving led's but it's to power big constant currant drivers 30V/1000mh range) and a lot more than 6 pwm channels. I could get a mega but i was looking for ic's. 16/24 channel and daisy chain able.
EVP:
I could get a mega but i was looking for ic's.
The AtMega168 is an IC (power and gnd is all that is needed in a bare minimum configuration) and for 60 channels you could get 10 of them and interface them pretty much any way you like.
i dont understand, i am already using a arduino uno for controlling, why would i use another atmel chip just for extra pwm output's ?
EVP:
i dont understand, i am already using a arduino uno for controlling, why would i use another atmel chip just for extra pwm output's ?
Most integrated circuits are just pre-programmed controllers designed to meet some specific market demand. A microcontroller on the other hand is general purpose and must be programmed to serve a specific purpose for which alternatives are either non-existing or cost prohibitive.
As an example it would be very easy to program just about any 16-pin microcontroller to emulate/act as a 74HC595 shift register. There really is no need to do so however since shift registers are available from “everywhere” at a low cost.
A through-hole PWM controller IC on the other hand is a bit harder to find and so creating one yourself may be a real alternative. PWM is just a modest challenge for the likes of an AtMega168 micro controller. You could program it using the Arduino core/libraries and could even add the logic to support a cascaded serial interface if this is what you really want. To scale up the project, you would just add a new microcontroller (your pre-programmed PWM IC) for every group of 6 channels. Your Uno/Duemillanove would still act as the main application controller.
I saw a project that did this exact thing, it was really cool and i was thinking of emulating it. They had a bunch of micros and some simple serial interface and they could expand it very easily. Look up the next house party system. It's at mit... Of course haha