Datasheet

Clocking
Intel
®
Quark™ microcontroller D2000
Datasheet January 2016
58 Document Number: 333577-002EN
- In “Low Power Compute” state of SoC, hybrid oscillator can be scaled down to
4 MHz with prescaler of 32 to get 125 kHz; or 32.768kHz (RTC clock wherein
hybrid oscillator can be powered down).
In a minimalistic system configuration that does not require RTC clock or strict clock
accuracy (< 100ppm) of system clock, such platforms can choose not to mount
32.768kHz XTAL and/or not to mount 32MHz XTAL and choose to work with 32MHz
Silicon RC oscillator mode of hybrid oscillator. Intel
®
Quark™ microcontroller D2000 is
designed to work with system clock only and does not mandate 32.768kHz RTC clock
for power state transitions, if system/platform does not require RTC clock for its
usecases.
7.2.1 System Clock - Hybrid Oscillator
When the system clock is sourced internally, a Cosmic Circuits hybrid oscillator [1] is
used to generate the clock. The hybrid oscillator can be run in two modes, crystal or
silicon mode depending on the frequency accuracy and current consumption
requirements of the SoC. The hybrid oscillator contains the follow features:
• Crystal mode
o Generates 20-33 MHz clock
o +/-100ppm (dependent on crystal frequency tolerance)
o 2ms start-up time to reach +/-100ppm accuracy
• Silicon mode (default power up mode)
o Generates 4/8/16/32 MHz clock
o One time 10-bit factory trim
o +/-20,000ppm (after process trim)
o Temperature compensation block to limit frequency variation
o 2us start-up time to reach +/-20,000ppm accuracy
• 4mA @ 32MHz in crystal mode [silicon characterization at ~650 uA @ 32 MHz]
• 450uA @ 32 MHz in silicon mode
• 300nA power down leakage current
• Operates with a supply range of 1.62-1.98V
• Outputs a rail-to-rail swing of 1.62-1.98V
• Power down mode to reduce power consumption within the SoC
• Glitch free mux for switching between hybrid and crystal oscillator clocks
• Bypass mode allows an external clock (fed through HYB_XTALI pin) to be
provided through the hybrid oscillator. HYBOSC has to be configured in Crystal
bypass mode (OSC0_EN_CRYSTAL=1, OSC0_EN_MODE_SEL=1,
OSC0_BYP_XTAL=1)
•
7.2.2 RTC Oscillator
A Silicon Gate Oscillator [2] is used to generate a 32.768kHz RTC clock. The RTC
oscillator has the following features:
• Voltage operating range of 1.08-1.98V
• Accuracy of +/-20ppm
• Nominal current consumption of 150nA
• Power down mode consumption of 100nA [TBC]