Post by thread:[OT] (?) 3 or 4 PWM IC

Hello, I'm not sure if this is OT, so I put it here to be sure. I am looking for an IC with 3 or 4 hardware pulse width modulators, with any kind of interface (I2C, SPI, etc). My current project is to make accent lights for my apartment using red/blue/green + white LEDs. I didn't see any PICs with 4 PWMs, but I have found some almost suitable solutions: Phillips makes the PCA 9530/1/2/3, an I2C LED dimmer with 2 to 16 bit I/O - though each model has only two PWMs total. Also, the SO form parts don't seem to actually be purchasable. The MAX 7313/4/5/6 are similar, though they have PWM on each I/O bit. This IC, however, has only 16 preset PWM steps, and comes only in QFN/QSOP packages. Is anyone familiar with an IC that might work? Something with 3 or 4 PWMs in SO/DIP would be ideal, it doesn't need to drive the LEDs directly like the chips above. Thank you, Ian

Ian, Scott Dattalo has nice 8 pwm routine I do not think you need any other hardware. His routine can control 8 pwm simultaneously. http://www.dattalo.com/technical/software/pic/pwm8.asm Andre spam_OUTianlesnetTakeThisOuTcwazy.co.uk wrote: {Quote hidden}>Hello, > >I'm not sure if this is OT, so I put it here to be sure. > >I am looking for an IC with 3 or 4 hardware pulse width modulators, with >any kind of interface (I2C, SPI, etc). My current project is to make >accent lights for my apartment using red/blue/green + white LEDs. I >didn't see any PICs with 4 PWMs, but I have found some almost suitable >solutions: > >Phillips makes the PCA 9530/1/2/3, an I2C LED dimmer with 2 to 16 bit I/O >- though each model has only two PWMs total. Also, the SO form parts >don't seem to actually be purchasable. > >The MAX 7313/4/5/6 are similar, though they have PWM on each I/O bit. >This IC, however, has only 16 preset PWM steps, and comes only in QFN/QSOP >packages. > >Is anyone familiar with an IC that might work? Something with 3 or 4 PWMs >in SO/DIP would be ideal, it doesn't need to drive the LEDs directly like >the chips above. > >Thank you, > >Ian > > > > > >

On Sun, 2005-08-07 at 16:05 +0100, .....ianlesnetKILLspam@spam@cwazy.co.uk wrote: > Hello, > > I'm not sure if this is OT, so I put it here to be sure. > > I am looking for an IC with 3 or 4 hardware pulse width modulators, with > any kind of interface (I2C, SPI, etc). My current project is to make > accent lights for my apartment using red/blue/green + white LEDs. I > didn't see any PICs with 4 PWMs, but I have found some almost suitable > solutions: I'm not sure where you were looking, but several of the dsPICs have 4 PWM outputs. Check any of the motor control family dsPICs. The 3011, 4011 and 4013 all have 4 PWM channels. If you need more then 4 the 5011, 5013, 6010, 6011, 6012, 6013 and 6014 all have 8 outputs, however they are not available in DIP. TTYL ----------------------------- Herbert's PIC Stuff: http://repatch.dyndns.org:8383/pic_stuff/

For something that slow, maybe banging it out in firmware is a better approach. But another option is something like 2 - 16F737's. You get 3 PWM's each and I2C. Of if you're really hung up about real estate, there are a couple of TQFP's with 5 PWMs. Another apporach would be to go to something like the 30F2010 with 6. --McD {Original Message removed}

ianlesnet@cwazy.co.uk wrote: > Hello, > > I'm not sure if this is OT, so I put it here to be sure. > > I am looking for an IC with 3 or 4 hardware pulse width modulators, with > > Is anyone familiar with an IC that might work? Something with 3 or 4 PWMs > in SO/DIP would be ideal, it doesn't need to drive the LEDs directly like > the chips above. Checkout TLC5940 from TI, available from Digikey. 16 pwm outputs, 12 bit resolution, serial data stream input, cascadable.

I use the 18F8722. It has 5 *hardware* PWM channels. Charles Linquist Marcel Duchamp wrote: {Quote hidden}> ianlesnetKILLspamcwazy.co.uk wrote: > >> Hello, >> >> I'm not sure if this is OT, so I put it here to be sure. >> >> I am looking for an IC with 3 or 4 hardware pulse width modulators, with >> >> Is anyone familiar with an IC that might work? Something with 3 or 4 PWMs >> in SO/DIP would be ideal, it doesn't need to drive the LEDs directly like >> the chips above. > > > Checkout TLC5940 from TI, available from Digikey. > > 16 pwm outputs, 12 bit resolution, serial data stream input, cascadable. >

> I'm not sure if this is OT, so I put it here to be sure. Definitely [EE] ! > I am looking for an IC with 3 or 4 hardware pulse width modulators, > with > any kind of interface (I2C, SPI, etc). My current project is to > make > accent lights for my apartment using red/blue/green + white LEDs. I > didn't see any PICs with 4 PWMs, but I have found some almost > suitable > solutions: You've had lots of suggestions, but here's a few comments. You could definitely use software PWM for LEDs (probably with interrupt drive) on many processors. 8 channels would be easy. The only limitation would be if you wanted a very large number of steps - but this is unlikely for LEDs. Maybe if you needed a large combined colour space. With say 4 channels and 64 steps, to get say 1 kHz frame rate you need 64 kHz bit rate or about 60 uS interrupt rate. If you used a PIC at 20 MHz that would give around 300 instructions per cycle. Ample room with time to do lots else as well. Many AVRs have 4 PWM or more. eg ATMega44 family have 4 (or is it 6). A capable device with many other hardware features (UART, IIC, A2D, ...) and a free (gulp) BASIC compiler (BASCOM) available for it. I think one of the Philip's LPC family has 8 x hardware PWM. (8051 based processor). RM

Thank you all for the great suggestions. I ordered a few TLC5490s to play with, I think this is the chip I was looking for. Serial interface, 16 PWMs, and available in DIP. I would love to try the 18f8722, but I'm not yet able to work with such small components. I will definitely keep it in mind though. Cheers, Ian Russell McMahon wrote: {Quote hidden}>> I'm not sure if this is OT, so I put it here to be sure. > > > Definitely [EE] ! > >> I am looking for an IC with 3 or 4 hardware pulse width modulators, with >> any kind of interface (I2C, SPI, etc). My current project is to make >> accent lights for my apartment using red/blue/green + white LEDs. I >> didn't see any PICs with 4 PWMs, but I have found some almost suitable >> solutions: > > > You've had lots of suggestions, but here's a few comments. > > You could definitely use software PWM for LEDs (probably with interrupt drive) on many processors. 8 channels would be easy. > The only limitation would be if you wanted a very large number of steps - but this is unlikely for LEDs. Maybe if you needed a large combined colour space. With say 4 channels and 64 steps, to get say 1 kHz frame rate you need 64 kHz bit rate or about 60 uS interrupt rate. If you used a PIC at 20 MHz that would give around 300 instructions per cycle. Ample room with time to do lots else as well. > > Many AVRs have 4 PWM or more. > eg ATMega44 family have 4 (or is it 6). > A capable device with many other hardware features (UART, IIC, A2D, ...) and a free (gulp) BASIC compiler (BASCOM) available for it. > > I think one of the Philip's LPC family has 8 x hardware PWM. > (8051 based processor). > > > > RM