> Why don't you just use 5 PIC port pins? Hm, that could be an option, but I'd rather not use that much pins. I've only got 6 pins left on the PIC18F452 and I'd like to keep those. The fewer pins used the better. > The two wire bi-colour LED's usually require the supply voltage > polarity to be reversed to change the colour. To control them from > a PIC would require an H-pack (or bridge) configuration. One wire > of the LED's to connect to a voltage divider giving half supply > voltage and the other wire to a pipolar PIC I/O pin so that when > the PIC output goes high it gives polarity for red and when low > it gives polarity for green. You still have to work out how to > control the LED's when you want them both off. An easier method > might be to regonfigure your design so that tou can use 3 wire > bi-colour led"s Well, using 1 PIC port for each LED is out of the question. Using 3-wire bi-color LEDs is out of the question, since the switches only have 2 holes to mount a LED into. Well, unless you know of a nice switch that cathers for 3-wire LEDs. I've browsed the whole Farnell catalog for useable switches and the Mec Multimec 3F were by far the nicest, although I have to admit that they are pretty expensive :(. I asked samples, when I receive them, I'll see if it is possible to drill an extra hole in the switch so that 3-pins LEDs can be mounted. I'm afraid it won't be possible though. > I *think* you would need 16 pins to control 8 * 2-pin LEDs. If so, you > could either connect 2 * 8-bit SRs serially and have each LED to an > adjacent pair of SR o/ps or use the SRs in parallel with the LEDs > between them (ie SR1d0 - LED+R - SR2d0), which amounts to the > same thing except 1 * 16-bit is a little simpler to i/f to > > OTOH Maxim et al are always putting out new LED controller ICs I'd like PWM to be able to dim the LEDs at night, for example when I want to fall asleep with music playing, so that I don't get disturbed by the bright LEDs. A blink function would be good too, that would free up the I2C bus (or the SPI bus of course) when I need to blink the LEDs. I saw that the MAX7314 has a blink input & PWM support, but it can only source current, so it's no good either. Does anybody know of a chip that can both source & sink current (10-15 mA per I/O should be fine) and that has blink & PWM output support? It looks like Philips has got an even beter chip, the PCA9532, it does the blinking on it's own, but it can't source current either. Hm, what about using a chip such as the Philips PCA9532 and let it drive 2 octal buffers such as the 74HC541. Could that work? If course it takes up a lot more space which isn't all that good either, but it's still better than occupying the I2C bus all the time. Help! I just spend 3 hours searching the net for a chip that has I2C/SPI control, 16 outputs, blink & PWM function and that can both sink & source current and nothing turned up :(. Regards, Anthony Van Herrewege PS: I added info on the preamp I'm making to my website, check it out here: http://members.lycos.nl/anthonvyh/index.php?page=preamp-main. Oh, and if you see anything stupid (and I'm sure the circuit's full of stupid mistakes), please inform me about it. Thanks! Website: http://members.lycos.nl/anthonyvh --------------------------------- Do you Yahoo!? Take Yahoo! Mail with you! Get it on your mobile phone. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics