HCS08 datasheet(312/374 Pages) NXP

312 / 374 page

Universal Serial Bus Device Controller (S08USBV1)

MC9S08JM60 Series Data Sheet, Rev. 5

312

Freescale Semiconductor

17.4.1.5

USB On-Chip Voltage Regulator (VREG)

The on-chip 3.3-V regulator provides a stable power source to power the USB internal transceiver and

provide for the termination of an internal or external pullup resistor. When the on-chip regulator is enabled,

it requires a voltage supply input in the range from 3.9 V to 5.5 V, and the voltage regulator output will be

in the range of 3.0 V to 3.6 V.

With a dedicated on-chip USB 3.3-V regulator and a separate power supply for the MCU, the MCU and

USB can operate at different voltages (See the USB electricals regarding the USB voltage regulator

electrical characteristics). When the on-chip 3.3-V regulator is disabled, a 3.3-V source must be provided

through the VUSB33 pin to power the USB transceiver. In this case, the power supply voltage to the MCU

must not fall below the input voltage at the VUSB33 pin.

The 3.3-V regulator has 3 modes including:

•

Active mode — This mode is entered when USB is active. Current requirement is sufficient to

power the transceiver and the USBDP pullup resistor.

•

Standby — The voltage regulator standby mode is entered automatically when the USB device is

in suspend mode. When the USB device is forced into suspend mode by the USB bus, the firmware

must configure the MCU for stop3 mode. In standby mode, the requirement is to maintain the

USBDP pin voltage at 3.0 V to 3.6 V, with a 900

Ω (worst-case) pullup.

•

Power off — This mode is entered anytime when stop2 or stop1 is entered or when the voltage

regulator is disabled.

17.4.1.6

USB On-Chip USBDP Pullup Resistor

The pullup resistor on the USBDP line required for full-speed operation by the USB Specification Rev. 2.0

can be internal or external to the MCU, depending on the application requirements. An on-chip pullup

resistor, implemented as specified in the USB 2.0 resistor ECN, is optionally available via firmware

configuration. Alternatively, this on-chip pullup resistor can be disabled, and the USB module can be

configured to use an external pullup resistor for the USBDP line instead. If using an external pullup resistor

on the USBDP line, the resistor must comply with the requirements in the USB 2.0 resistor ECN found at

http://www.usb.org.

The USBPU bit in the USBCTL0 register can be used to indicate if the pullup resistor is internal or external

to the MCU. If USBPU is clear, the internal pullup resistor on USBDP is disabled, and an external USBDP

pullup can be used. When using an external USBDP pullup, if the voltage regulator is enabled, the VUSB33

voltage output can be used with the USBDP pullup. While the use of the internal USBDP pullup resistor

is generally recommended, the figure below shows the USBDP pullup resistor configuration for a USB

device using an external resistor tied to VUSB33.

HCS08 bảng dữ liệu(PDF) 312 Page - NXP Semiconductors

HCS08 bảng dữ liệu(HTML) 312 Page - NXP Semiconductors

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

bảng dữ liệu tải về

Link URL