USB Electrical Characteristics
shows signal timings during UTOPIA transmit operations.
U1
1
UtpClk
U2
5
PHSELn
U3
3
TxClav
High-Z at MPHY
TxEnb
UTPB
SOC
U2
2
High-Z at Multi-PHYP
U4
4
U1
U2
5
Figure 71. UTOPIA Transmit Timing
14 USB Electrical Characteristics
This section provides the AC timings for the USB interface.
14.1 USB Interface AC Timing Specifications
The USB Port uses the transmit clock on SCC1.
lists the USB interface timings.
Table 33. USB Interface AC Timing Specifications
All Frequencies
Name
US1
USBCLK frequency of operation
Low speed
Full speed
Characteristic
Min
1
Unit
Max
6
48
45
55
MHz
MHz
%
US4
USBCLK duty cycle (measured at 1.5 V)
1
USBCLK
accuracy should be ±500 ppm or better. USBCLK may be stopped to conserve power.
15 FEC Electrical Characteristics
This section provides the AC electrical specifications for the fast Ethernet controller (FEC). Note that the timing
specifications for the MII signals are independent of system clock frequency (part speed designation). Also, MII
signals use TTL signal levels compatible with devices operating at either 5.0 V or 3.3 V.
MPC885/MPC880 Hardware Specifications, Rev. 3
71
Freescale Semiconductor
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
