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Topic: Why 32u4 and not 32u4RC? (Read 534 times) previous topic - next topic

vputz

Just curious, since I'm trying to build a Leonardo-compatible-ish board... I see the 32u4RC-AU chip out there with a built in oscillator, but the leo and most other boards use an external crystal with the non-RC chip.  Is there a reason to avoid the internal oscillator?  Is it just not accurate enough?

Coding Badly


http://www.atmel.com/devices/atmega32u4.aspx?tab=documents

Quote
21.4 Crystal-less operation
To reduce external components count and BOM cost, the USB module can be configured to operate in low-speed mode with internal RC oscillator as input source clock for the PLL. The internal RC oscillator is factory calibrated to satisfy the USB low speed frequency accuracy within the 0°C and -40°C temperature range.

For USB full-speed operation only external crystal oscillator or external source clock can be used.

vputz

Thanks; exactly what I was looking for, clear and unambiguous.  Sorry I missed it.

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