MPC870 FREESCALE [Freescale Semiconductor, Inc], MPC870 Datasheet - Page 67

• Manufacturer Part Number: MPC870
• Description: Hardware Specifications
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

USB Electrical Characteristics
Figure 63
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.
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.
15.1 MII and Reduced MII Receive Signal Timing
The receiver functions correctly up to a MII_RX_CLK maximum frequency of 25 MHz +1%. The reduced MII
(RMII) receiver functions correctly up to a RMII_REFCLK maximum frequency of 50 MHz + 1%. There is no
minimum frequency requirement. In addition, the processor clock frequency must exceed the MII_RX_CLK
frequency – 1%.
67
1
Name
USBCLK accuracy should be ± 500 ppm or better. USBCLK may be stopped to conserve power.
US1
US4
SDA
SCL
shows the I
USBCLK frequency of operation
Low speed
Full speed
USBCLK duty cycle (measured at 1.5 V)
205
202
2
C bus timing.
206
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
Table 30. USB Interface AC Timing Specifications
MPC875/MPC870 Hardware Specifications, Rev. 3.0
203
Figure 63. I
1
Characteristic
207
Table 30
209
2
C Bus Timing Diagram
lists the USB interface timings.
204
210
208
All Frequencies
Min
45
211
Freescale Semiconductor
48
6
Max
55
MHz
MHz
Unit
%