Micro with 4-independent PWM channels

> guess you forgot something about the clocks. While Philips seems top be
> more conservative about the flash access time, specofying it with
> approx 50 ns access time over temperature, Atmel claims 33 ns quite
> good.

At room temp, the SAM7 runs zero waitstate at 48 MHz.


> Now about the cycles.  While Philips might need a clock cycle more at
> 60 MHz compared to a SAM7 at 30 MHZ to execute the first instruction
> after a branch that leaves it still a lot faster. SAM7 has the max
> throughput @ 30 MHz, LPC2000 @ 60 MHz. The cycles you mentioned are
> clock cycles not bus cycles ;-)

In Thumb mode, your highest throughput is when you run it in max frequency
or 55 MHz.

> We tested the port switching and because the ports are connected to the
> peripheral bus the limit is 4 MHz while Atmel can do a little more than
> 5 MHz connected to the AHB.  Point taken and accepted. Unfortunately
> you have to run the SAM7 with wait states when doing that. Running at
> 30 MHz which provides max. performance and best power / performance
> ratio gives you even less than 4 MHz switch frequency.

55 MHz from SRAM is faster and if you really need toggle speed, then there
is the SPI and SSCs.
Don't think the SSC is present on the LPC.

> According to a Philips presentation on the ARM developers conference
> there is a Data Bypass Buffer for data fetched from flash, it does not
> interfere with the instruction pipeline.

> The presentations I have seem from Atmel state a power consumption of
> approximately 50 mA @ 50 MHz, the measurement we did with the LPC2131
> showed 43 mA @ 60 MHz, giving twice the performance at less power, I
> have no idea where you got your power numbers from.  To be fair, we did
> not measure the SAM7 yet because the performance is just not enough for
> what we are doing.

Datasheet says 29-30 mA on the VccCore when the CPU runs at 50 Mhz.
Philips datasheet states this a little higher than 43 mA IIRC.

> USB is a good point for the Atmel devices, but the SAM7S32 does not
> have one or did I miss something?  The S64 pricing announced at the ARM
> devcon was 50% higher than that of the S32! USB comes at a price and
> with some delay.  Looking forward to the Philips USB devices as well.

The S64 of course adds an additional 32 kB flash and 8 KB SRAM.

> May be Philips uses a lower power process? because I would have
> expected the SAM7 to be lower power given the performance difference.

I think that the presentation you have is wrong.

> In the end we totally agree that both companies will be strong
> competitors and the ARM micros are highly competitive against high end
> 8-bit and the full range of 16-bit micros.


> btw. although we might somewhat disagree which devices to use I really
> appreciate your postings because you try very hard and successfully to
> stay on a technical level.


-- 
Best Regards
Ulf at atmel dot com
These comments are intended to be my own opinion and they
may, or may not be shared by my employer, Atmel Sweden.

Mike escreveu:
> I am looking for a PIC or Atmel Micro that has 4-independently
> controlled PWM channels of about 10-bit resolution . The frequnency
> can be the same but I need simultaneous 0-100% duty cycle control of
> each channel independently . The max PWM frequncy should be greater
> than 1KHz
> Price Range $2.00-$6.00/usd. A few A/D channels, interrupts,C-Compiler
> friendly. I have looked @ the PIC18F1220, however , I am not sure of
> independent PWM control, as the chip still only has one CCP?
> Thanks
> Mike
> 
You may add to the other suggestions the TI TMS320LF2401, but yuo'll 
have a startup cost somewhat high (no free tools).

Ricardo

Ricardo wrote:

> Mike escreveu:
> 
>> I am looking for a PIC or Atmel Micro that has 4-independently
>> controlled PWM channels of about 10-bit resolution . The frequnency
>> can be the same but I need simultaneous 0-100% duty cycle control of
>> each channel independently . The max PWM frequncy should be greater
>> than 1KHz
>> Price Range $2.00-$6.00/usd. A few A/D channels, interrupts,C-Compiler
>> friendly. I have looked @ the PIC18F1220, however , I am not sure of
>> independent PWM control, as the chip still only has one CCP?
>> Thanks
>> Mike
>>
> You may add to the other suggestions the TI TMS320LF2401, but yuo'll 
> have a startup cost somewhat high (no free tools).

..and another option, at the high end, would be the new
TMS470 ARM Flash uC from TI.
  From the info posted so far, it seems they have a 
timer-control-engine, somewhat similar to the Motorola TPU, on their 
timer channels.
  Has anyone used this ?

  Probably a tad overkill for 4 x 1KHz PWMs :)
-jg

In article <xsmdnW3PdY08mm_cRVn_vQ@giganews.com>,
Mike <chimera-electronics@sympatico-dot-ca.no-spam.invalid> wrote:
>I am looking for a PIC or Atmel Micro that has 4-independently
>controlled PWM channels of about 10-bit resolution . The frequnency
>can be the same but I need simultaneous 0-100% duty cycle control of
>each channel independently . The max PWM frequncy should be greater
>than 1KHz
>Price Range $2.00-$6.00/usd. A few A/D channels, interrupts,C-Compiler
>friendly. I have looked @ the PIC18F1220, however , I am not sure of
>independent PWM control, as the chip still only has one CCP?
>Thanks
>Mike
>

Rabbit 3000A has 4 independent 10bit PWM, interrupts, and has C
support. You'll need an external A/D (it has hardware SPI) and 
it's more than $6.00.

	http://rabbitsemiconductor.com/products/rab3000/

See ya, -ingo
-- 
/* Ingo Cyliax, cyliax@ezcomm.com, Tel: 812-391-0895 */

Jim Granville wrote:
> ..and another option, at the high end, would be the new
> TMS470 ARM Flash uC from TI.
>  From the info posted so far, it seems they have a timer-control-engine, 
> somewhat similar to the Motorola TPU, on their timer channels.
>  Has anyone used this ?
> 
>  Probably a tad overkill for 4 x 1KHz PWMs :)

  Following up, I see a press release today
http://www.eeproductcenter.com/micro/review/showArticle.jhtml?articleID=57702943

that claims these are TMS470R1A64 @ $4.95/1K, and are available now, (so 
that was a faster release ramp than some) ....
-jg

R Adsett wrote:
> I've had this assertion made to me several times.  So far no-one has been 
> able to back it up.  A CPLD capable of holding 4 10 bit PWMs always seems 
> to be rather more expensive than a few dollars (You still have to add A/D 
> micro etc and fit in the $6 range remember). 
> 
> From what I've seen so far it's always cheaper to add another micro to 
> act as a PWM peripheral that to add a CPLD to do the same thing.
> 
> That's not to say it's impossible, but so far no-ones been able to 
> demonstrate that it's doable.
> 
> Robert

Agreed.  Why doesn't someone sell a dedicated chip as a PWM expander? 
It would be nice to find a SPI or I2C - compatible chip with 6 to 8 PWM 
outputs, at least 14 bits, for LED lighting applications.  Preferably in 
  a 14 or 16 -pin package, 5V compatible outputs.

All the micros are skimpy on hi-resolution PWM outputs.

mw

On Sat, 29 Jan 2005 14:07:02 GMT, mw <mw@avoidspam.com> wrote:

>R Adsett wrote:
>> I've had this assertion made to me several times.  So far no-one has been 
>> able to back it up.  A CPLD capable of holding 4 10 bit PWMs always seems 
>> to be rather more expensive than a few dollars (You still have to add A/D 
>> micro etc and fit in the $6 range remember). 
>> 
>> From what I've seen so far it's always cheaper to add another micro to 
>> act as a PWM peripheral that to add a CPLD to do the same thing.
>> 
>> That's not to say it's impossible, but so far no-ones been able to 
>> demonstrate that it's doable.
>> 
>> Robert
>
>Agreed.  Why doesn't someone sell a dedicated chip as a PWM expander? 
>It would be nice to find a SPI or I2C - compatible chip with 6 to 8 PWM 
>outputs, at least 14 bits, for LED lighting applications.  Preferably in 
>  a 14 or 16 -pin package, 5V compatible outputs.
>
>All the micros are skimpy on hi-resolution PWM outputs.
>

For LED Driving applications Maxim makes a number of ICs which can
directly drive numerous LEDs. The current can be set individually for
each LED. It does not use PWM, so for EMI it is better. Look at
something like the MAX6957AAI, available at Digikey in small
quantities.

Anton Erasmus

On Sat, 29 Jan 2005 14:07:02 GMT, the renowned mw <mw@avoidspam.com>
wrote:

>R Adsett wrote:
>> I've had this assertion made to me several times.  So far no-one has been 
>> able to back it up.  A CPLD capable of holding 4 10 bit PWMs always seems 
>> to be rather more expensive than a few dollars (You still have to add A/D 
>> micro etc and fit in the $6 range remember). 
>> 
>> From what I've seen so far it's always cheaper to add another micro to 
>> act as a PWM peripheral that to add a CPLD to do the same thing.
>> 
>> That's not to say it's impossible, but so far no-ones been able to 
>> demonstrate that it's doable.
>> 
>> Robert
>
>Agreed.  Why doesn't someone sell a dedicated chip as a PWM expander? 
>It would be nice to find a SPI or I2C - compatible chip with 6 to 8 PWM 
>outputs, at least 14 bits, for LED lighting applications.  Preferably in 
>  a 14 or 16 -pin package, 5V compatible outputs.

There are zillions of such chips in large scale LED video displays
(the USD 1E6 per display kind). 


Best regards, 
Spehro Pefhany
-- 
"it's the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

In article <1107011240.3cbc39f81340bf9c5fc466330cb326b9@teranews>, 
nobody@spam.prevent.net says...
> On Sat, 29 Jan 2005 14:07:02 GMT, mw <mw@avoidspam.com> wrote:
> 
> >R Adsett wrote:
> >> I've had this assertion made to me several times.  So far no-one has been 
> >> able to back it up.  A CPLD capable of holding 4 10 bit PWMs always seems 
> >> to be rather more expensive than a few dollars (You still have to add A/D 
> >> micro etc and fit in the $6 range remember). 
> >> 
> >> From what I've seen so far it's always cheaper to add another micro to 
> >> act as a PWM peripheral that to add a CPLD to do the same thing.
> >> 
> >> That's not to say it's impossible, but so far no-ones been able to 
> >> demonstrate that it's doable.
> >> 
> >> Robert
> >
> >Agreed.  Why doesn't someone sell a dedicated chip as a PWM expander? 
> >It would be nice to find a SPI or I2C - compatible chip with 6 to 8 PWM 
> >outputs, at least 14 bits, for LED lighting applications.  Preferably in 
> >  a 14 or 16 -pin package, 5V compatible outputs.
> >
> >All the micros are skimpy on hi-resolution PWM outputs.
> >
> 
Not so.  Any of the Motorola (Freescale)  micros with a TPU can have
up to 16  high-resolution PWM outputs.   They're a bit big and
expensive to use as a PWM peripheral, though.  ;-)


> For LED Driving applications Maxim makes a number of ICs which can
> directly drive numerous LEDs. The current can be set individually for
> each LED. It does not use PWM, so for EMI it is better. Look at
> something like the MAX6957AAI, available at Digikey in small
> quantities.
> 

Mark Borgerson

>Subject: Re: Micro with 4-independent PWM channels

>Agreed.  Why doesn't someone sell a dedicated chip as a PWM expander? 
>It would be nice to find a SPI or I2C - compatible chip with 6 to 8 PWM 
>outputs, at least 14 bits, for LED lighting applications.  Preferably in 
>  a 14 or 16 -pin package, 5V compatible outputs.
>
>All the micros are skimpy on hi-resolution PWM outputs.

For LED driving it's so so easy to program allmost any micro to perform this
function. You dont need  dedicated PWM chanells, you can do it in software as
long as the frequency is not too high.