Clocking
Freedom Board for Kinetis K28F (FRDM-K28F), User's Guide, Rev. 0, 04/2017
10
NXP Semiconductors
Table 3. MK28FN2M0VMI15 MCU features
Feature
Description
Performance
•
Up to 150 MHz ARM Cortex-M4-based core with DSP instructions and a
single precision floating-point unit.
Memory and memory expansion
•
2 MB program flash memory and 1 MB RAM.
•
Dual QuadSPI with XIP.
•
FlexBus external bus interface and SDRAM controller.
Analog modules
•
One 16-bit SAR ADC, two 6-bit DACs, and one 12-bit DAC.
•
Two analog comparators (CMP) containing a 6-bit DAC and a
programmable reference input.
•
Voltage reference: 1.2 V.
Communication interfaces
•
USB high-speed device/host.
•
USB full-/low-speed on-the-go controller with the device charge detect
capability.
•
Secure Digital Host Controller (SDHC).
•
FlexIO.
•
Two I
2
S modules, four SPI modules (SPI3 supports more than 40 Mbit/s),
four I
2
C modules, and five LPUART modules.
Security
•
Hardware random-number generator.
•
Supports DES, AES, and SHA accelerator (CAU).
•
Cyclic Redundancy Check (CRC).
•
Multiple levels of embedded flash security.
Timers
•
One 4-channel 32-bit periodic interrupt timer.
•
Two 16-bit low-power timer PWM modules.
•
Two 8-channel motor-control/general-purpose/PWM timers.
•
Two 2-channel quadrature decoder/general-purpose timers.
•
Real-time clock with an independent 3.3 V power domain.
•
Programmable delay block.
Human machine interface
•
Up to 120 general-purpose inputs/outputs.
Operating Characteristics
•
Main VDD voltage and flash write voltage range: 1.71 V
–3.6 V.
•
Temperature range (ambient): -40
–105°C.
•
Independent VDD_CORE: 1.17 V-1.47 V.
•
Independent VDDIO for PORTE (QuadSPI): 1.71 V
–3.6 V.
•
Independent VBAT (RTC): 1.71 V
–3.6 V.
5. Clocking
CAUTION
The resonator is not recommended when the HS USB is used.
The K28F MCU starts up from an internal Digitally-Controlled Oscillator (DCO). Software can enable
the main external oscillator (EXTAL0/XTAL0) if desired. The external oscillator/resonator can range
from 32.768 kHz up to 32 MHz. The default external source for the MCG oscillator inputs (EXTAL) is
the 12 MHz crystal, which is configured to operate in the low-power mode, so the feedback resistor
(R78) is not needed. The 12 MHz reference clock is suitable for both the audio codec and the HS USB
features.
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