PWM ICs

Hello Everyone,

I've lurked for a time, but this is my first post. I'm using an LPC2294 i an automotive application. The on-board PWM module has a total of channels, and only 3 of which can be used to program double edged. Th loading is such, the LPC's PWM module cannot handle the bandwidth. I nee a programmable 6 - 12 (independent) channel IC for pulse generation. SP or I2C slaves preferred. The resolution requirements are not great. Th (negative going) pulse widths I'll need are in the range .5 ms to 25 ms I've done quite a bit of searching on the internet, but nothing reall seems to match my requirements. Unless I come up with an appropriat component I'll consider a PIC or other MCU as a dedicated SPI or I2C slav to the Philips part. Can I get anyone's and everyone's $.02 on potentia alternatives. The component price is not a huge factor, but I'd like t keep it $15 or below.

Regards,

Steve Clevenger

Reply to
Steve_Clevenger
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With all that you've described, I would be leaping for a small micro. I happen to dislike the PIC family, so I would probably be headed for an AVR, but whatever tickles your pickle...

Reply to
larwe

"Steve_Clevenger" skrev i meddelandet news:66-dnRgnVJQP snipped-for-privacy@giganews.com...

No need to search further... The ARM7TDMI based AT91SAM7A3 has 9 independent general purpose counters with dual PWM. On top of that is has a PWM unit with 4 counters each with dual PWM for a total of 26 PWM outputs. Just get rid of the nasssty LPC and you are in business for much less than $15.

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Best Regards,
Ulf Samuelsson
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Reply to
Ulf Samuelsson

I looked at the chip out of curiousity and I must say I am impressed. All that at much less than $15... really good. Are the programming sequences obtainable? (I mean so I can adapt my JTAG tools, not having to buy anyone elses).

Dimiter

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Ulf Samuelss> "Steve_Clevenger" skrev i meddelandet

Reply to
Didi

"Didi" skrev i meddelandet news: snipped-for-privacy@g10g2000cwb.googlegroups.com...

You need to program the Samba Bootloader into the flash. There is a free version on

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somewhere in the SAM7 forum. Check if your tools support AT91SAM7 or get the SAM-ICE for $129. You can download the Atmel Samba PC S/W for free.

Best Regards, Ulf Samuelsson This is intended to be my personal opinion which may, or may not be shared by my employer Atmel Nordic AB

Reply to
Ulf Samuelsson

than

The LPC probably has to stay. The working plan is to source the primar CPU module (CPU card) from Phytec or elsewhere. I'm ultimately trying t maintain 3U x 160mm dimensions. I considered one or two Atmel parts, but wanted more clock than what I saw available off-the-shelf, and I had n information how high these parts had successfully been clocked. With it' feature set, the Atmel may otherwise make for a nice slave.

Steve C.

Reply to
Steve_Clevenger

Have you considered a CPLD or one of the really cheap FPGAs (like the Spartan)? You may approach $15 from above rather than below, but I think there's ones out there that are close.

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Tim Wescott
Wescott Design Services
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Reply to
Tim Wescott

You should clarify that: - do you mean the SW loading is too slow, or the PWM frequency is somehow wrong, or ?

There are LED drivers that do mulichannel PWM dimming, but they are likely to be too LED focused. That leaves CPLD and uC.

A good tiny uC that will do Slave PWM, is ATmel (new) AT89LP213. That has two 8 bit HW PWM, and buffered SPI, in TSSOP14, so sprinkle 3-6 of those about. The core is fast enough, to handle fault protection

If SW PWM is also OK, the larger LP2052 has more pins, so could manage SW PWM.

CPLD can also do this, but tend to have less than ideal resource/pin count ratios - they are a good fall-back, if no uC solution can be found.

-jg

Reply to
Jim Granville

This application uses HW PWM. The basic problem with the LPC is the PW channels are not completely independent, and there's not enough of them The PWM MR0 match register establishes the cycle rate (period) for PW channels 1 - 6. Within a particular cyle, you can use channels as singl edge (6 channels), or double edge (3 channel limit due to the overlap o match register assignments). Consider this a PWM bank. Suppose it' possible to muliplex (reuse) these channels using a CD4053 or some such If you need an available channel for a 10 ms pulse every 5 ms everythin looks good until pulse #4 where an overrun of 5 ms is suffered before th first channel is available to reuse/reprogram. I'll have significantl more traffic than that. I think the primary requirement is channe independence. If I can find such a usage model, I won't need as man channels.

Steve C.

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Reply to
Steve_Clevenger

than

The LPC probably has to stay. The working plan is to source the primar CPU module (CPU card) from Phytec or elsewhere. I'm ultimately trying t maintain 3U x 160mm dimensions. I considered one or two Atmel parts, but wanted more clock than what I saw available off-the-shelf, and I had n information how high these parts had successfully been clocked. With it' feature set, the Atmel may otherwise make for a nice slave.

Steve C.

Reply to
Steve_Clevenger

SAM7A3 can be clocked at 60 Mhz.

1 waitstate on flash so copy critical routines/interrupts to its internal 32 kB SRAM. Thumb mode will be faster than ARM mode.

You might also consider the AT90PWM3 as a nice slave. Has 3 PWM channels with positive + negative PWM.

2 x AT90PWM3 should be cheaper than one SAM7A3
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Best Regards,
Ulf Samuelsson
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Reply to
Ulf Samuelsson

Ulf,

Thanks. The AT90PWM3 learning curve may be more than I want to take o right now. That, and the fact I'll need 2-4 ea. for variou configurations. I'm interested in the SAM7A3, and I've seen the eval board available through two of the Atmel distribution channels. Do yo know of any board vendors that offer a deployable SAM7A3 CPU module (al Phytec), or have plans in the works to produce one?

Regards,

Steve C.

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Reply to
Steve_Clevenger

Ulf,

Thanks. The AT90PWM3 learning curve may be more than I want to take o right now. That, and the fact I'll need 2-4 ea. for variou configurations. I'm interested in the SAM7A3, and I've seen the eval board available through two of the Atmel distribution channels. Do yo know of any board vendors that offer a deployable SAM7A3 CPU module (al Phytec), or have plans in the works to produce one?

Regards,

Steve C.

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Reply to
Steve_Clevenger

"Steve_Clevenger" skrev i meddelandet news:wfednUBhlsow-u7ZnZ2dnUVZ snipped-for-privacy@giganews.com...

I only know of proprietary PCBs You could check w

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which has a number of SAM7 boards. Nothing announced with SAM7A3 yet. SAM7S,SAM7X and SAM7A2 is supported though.

--
Best Regards,
Ulf Samuelsson
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Reply to
Ulf Samuelsson

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