ARM7TDMI processors with 32-bit capture timers?

any from Atmel.

Philips, all of their ARM (LPC2000) timers appear to be 32bits.

Robert

any from Atmel.

Maybe Philips LPC213x series, and the TI TMS470's have advanced timers, with a small timer control unit (opcodes) ?.

-jg

"David Lawson" wrote I'm trying to find an ARM chip that has a 32 bit capture timer. I can't find any from Atmel.

The Philips LPC2000 series have 2 32 bit timers with 3 or 4 32 bit capture channels each.

Richard Tuffin

any from Atmel.

Yes, but in software. With a 65MHz input to the timer the overflow rate is

1 KHz and easily handled by a 6-instruction software interrupt routine. At ~1-2 MHz the rate is 30 - 60Hz. By reading the software counter before and after reading the hardware timer it is possible to get 100% reliable on-the-fly counts.

-- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. To reply, remove spaces: n o lindan at ix . netcom . com psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Never tried, but I think you can chain two 16 bit timers on the AT91. If you dont want to waste timers:

If you run at 50 Mhz, and have a top value of 50000, you also get a free clock tick for an operating system.

The clock tick will update the upper 16 bits for the 32 bit timer, and the capture interrupt will read from the SRAM location. Is this to reduce power consumption or to reduce interrupt rates?.

--
Best Regards,
Ulf Samuelsson

I was thinking of trying to connect timer2 to timer1 to see if I can get a 32 bit capture to work. I wasn't sure if that would work. I'm using tioa2 to get a 16 bit capture. I'll give that a try.

I may need to read some very low rpm's, so 16 bits might not be enough.

I'm running timer0 as the system timer.

David