TWR-K60N512-KEIL Freescale Semiconductor, TWR-K60N512-KEIL Datasheet - Page 130

• Manufacturer Part Number: TWR-K60N512-KEIL
• Description: K60N512 Keil Tower Kit
• Manufacturer: Freescale Semiconductor
• Series: Kinetisr
• Type: MCUr

Specifications of TWR-K60N512-KEIL

• Rohs Compliant: YES
• Contents: 4 Boards, Documentation, DVD
• Peak Reflow Compatible (260 C): Yes
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: Freescale Tower System, K60N512

Module configuration
14.5
Module configuration
14.5.1 Module dependencies
Clock Source
The USB module needs a 48 Mhz clock to operate. There are three possible sources for
the USB clock: PLL, FLL, and an external pin called USB_CLKIN. With PLL or FLL,
there is a fractional divider after the MUX. It divides the frequency of the PLL or FLL to
enable the MCU to operate at higher frequencies than 48 Mhz. The output of the
fractional divider goes to a MUX, and then a choice is made between this signal and the
USB_CLKIN pin. The fractional divider value can be configured in the SIM_CLKDIV2
register inside the system integration module (SIM).
Figure 14-5. USB clock diagram
Voltage Regulator
The USB transceiver power supply comes directly from VOUT33 (voltage regulator
output). Therefore, the regulator must be enabled to supply 3.3 V to the transceiver.
14.5.2 USB initialization process
The USB module can work in either device or host mode. During initialization the two
modes are similar, but there are minor differences between the two.
Device Mode Initialization
In device mode the USB module activates the pullup resistor after initialization is
complete, to be detected by the remote host.
Kinetis Quick Reference User Guide, Rev. 0, 11/2010
130
Freescale Semiconductor