SAMA5D3 timer speed

Discussion around products based on ARM Cortex-A5 core.

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I.H.
Posts: 1
Joined: Fri Oct 11, 2013 2:40 pm

SAMA5D3 timer speed

Fri Oct 11, 2013 3:31 pm

Our company is currently designing a new hardware platform that must be able to very accurately measure time intervals. For this reason we are looking for a microcontroller that offers 32-bit timers with high clock speeds. The SAMA5D3 series MPU appear to offer fast timers so we are considering using this chip. However, I am not sure exactly how fast the timers in this chip are able to run.

I tried to find the required information in the SAMA5D3 datasheet (http://www.atmel.com/Images/Atmel_11121 ... asheet.pdf) but without complete success.

It appears that the following is true:
- Timer counter 0 uses the Pheripheral Clock as the clock input
- Pheripheral Clock is typically equal to MCK
- MCK can be driven by the PLLACK clock by configuring the PMC_MCKR register
- PLLACK is the output of the 400 to 1000MHz PLLA
- The PLLA clock must be divided by 2 by writing the PLLADIV2 bit in the PMC_MCKR register, resulting in an effective clock of 500MHz
- The Timer Counter 0 unit has a minimum clock input divider of 2 (div2), resulting in a maximum timer clock of 500/2 = 250MHz

I am however not at all sure if I have determined the maximum timer clock correctly. I am hoping that at least one of the two dividers does not have to be applied so that the TC0/1 are able to run at 500MHz.

Can someone give me clarification on this subject?

Suggestions on other Atmel chips that have fast timers (multiple-100-MHz) are also welcome.
Harbour
Posts: 23
Joined: Fri May 10, 2013 6:26 pm

Re: SAMA5D3 timer speed

Sun Oct 13, 2013 1:46 am

I'd rather use the fast FPGA with custom designed time measurement function attached to the MCU with any (even slow) bus than the MCU timer itself. Using FGPA is easily to achieve the picoseconds resolution which I think impossible with any MCU timers.
Rus
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SfinxSoft
http://sfinxsoft.com

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