Datasheet

Universal Serial Bus Device Controller (S08USBV1)
MC9S08JM60 Series Data Sheet, Rev. 3
300 Freescale Semiconductor
17.2 External Signal Description
The USB module requires both data and power pins. Table 17-3 describes each of the USB external pin
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.
Table 17-3. USB External Pins
Name Port Direction Function Reset State
Positive USB differential signal USBDP I/O Differential USB signaling.
High
impedance
Negative USB differential signal USBDN I/O Differential USB signaling.
High
impedance
USB voltage regulator power pin V
USB33
Power
3.3 V USB voltage regulator output
or 3.3 V USB transceiver/resistor
supply input.
—