Datasheet

Clocking
Intel
®
Quark™ microcontroller D2000
January 2016 Datasheet
Document Number: 333577-002EN 57
7 Clocking
The Intel
®
Quark™ microcontroller D2000 clocking is controlled by the Clock Control
Unit (CCU). There are 2 primary clocks in Intel
®
Quark™ microcontroller D2000, a
System clock and an RTC clock. The sources and frequencies of the primary clocks
are described in subsequent sections. The CCU uses the primary clocks to generate
secondary clocks to sub modules in the SoC. The secondary clocks are gated and
scaled versions of the primary clocks.
7.1 Signal Descriptions
Table 12 provides the dependency on external signals/pins on clocking. Change from
Atlas Peak is that there is no need to output system clock and RTC clock to platform.
Table 12. External Signals
Signal Name Direction/
Type
Description
External Crystal Interface
HYB_XTALI
I/O XTAL input or External system
clock
HYB_XTALO I/O XTAL input
RTC_XTALI I/O RTC XTAL input
RTC_XTALO I/O RTC XTAL input
SYS_CLK_OUT O Divided 32 MHz System Clock
output (pin multiplexed onto
pin F_5 and not dedicated)
RTC_CLK_OUT O 32 kHz RTC clock output (pin
multiplexed onto pin F_4 and
not dedicated)
7.2 Features
The CCU supports the following features:
- Supply of 32.768kHz RTC clock from internal crystal oscillator
- Supply of system clock from:
o an internal hybrid oscillator which can work in either 4/8/16/32 MHz
Silicon RC oscillator mode (+/- 2% clock accuracy) or 20-32 MHz
Crystal oscillator mode (+/- 100 ppm clock accuracy; depending on
crystal connected)
o an external clock source (through HYB_XTALI input pin)
o 32.768kHz RTC clock (internal muxing)
- Perform clock gating on all output clocks
- Perform clock scaling on all output clocks