MC9S08JM16 Datasheet, PDF (300/386 Pages) Freescale Semiconductor, Inc – Microcontrollers

Universal Serial Bus Device Controller (S08USBV1)
17.2 External Signal Description
The USB module requires both data and power pins. Table 17-3 describes each of the USB external pin
Table 17-3. USB External Pins
Name
Positive USB differential signal
Negative USB differential signal
USB voltage regulator power pin
Port
USBDP
USBDN
V_USB33
Direction
Function
I/O
Differential USB signaling.
I/O
Power
Differential USB signaling.
3.3 V USB voltage regulator output
or 3.3 V USB transceiver/resistor
supply input.
Reset State
High
impedance
High
impedance
—
17.2.1 USBDP
USBDP is the positive USB differential signal. In a USB peripheral application, connect an external
33 Ω ±1% resistor in series with this signal in order to meet the USB Specification Rev. 2.0 impedance
requirement.
17.2.2 USBDN
USBDN is the negative USB differential signal. In a USB peripheral application, connect an external
33 Ω ±1% resistor in series with this signal in order to meet the USB Specification, Rev. 2.0 impedance
requirement.
17.2.3 V_USB33
V_USB33 is connected to the on-chip 3.3 V voltage regulator (VREG). V_USB33 maintains an output voltage
of 3.3 V and can only source enough current for USB internal transceiver (XCVR) and USB pullup
resistor. If the VREG is disabled by software, the application must input an external 3.3 V power supply
to the USB module via V_USB33.
17.3 Register Definition
This section describes the memory map and control/status registers for the USB module.
MC9S08JM16 Series Data Sheet, Rev. 2
300
Freescale Semiconductor