Datasheet

MPC8308 PowerQUICC II Pro Processor Hardware Specification, Rev. 3
Freescale Semiconductor 17
Ethernet: Three-Speed Ethernet, MII Management
8.2 MII and RGMII AC Timing Specifications
The AC timing specifications for MII and RGMII are presented in this section.
8.2.1 MII AC Timing Specifications
This section describes the MII transmit and receive AC timing specifications.
8.2.1.1 MII Transmit AC Timing Specifications
This table provides the MII transmit AC timing specifications.
Table 22. RGMII DC Electrical Characteristics
Parameters Symbol Conditions Min Max Unit
Supply voltage 2.5 V LV
DD
—2.372.63V
Output high voltage V
OH
I
OH
= –1.0 mA LV
DD
= Min 2.00 LV
DD
+ 0.3 V
Output low voltage V
OL
I
OL
= 1.0 mA LV
DD
= Min VSS– 0.3 0.40 V
Input high voltage V
IH
—LV
DD
= Min 1.7 LV
DD
+ 0.3 V
Input low voltage V
IL
—LV
DD
= Min –0.3 0.70 V
Input high current I
IH
V
IN
1
= LV
DD
—15A
Input low current I
IL
V
IN
1
= VSS –15 — A
Note:
1. V
IN
, in this case, represents the LV
IN
symbol referenced in Table 1 and Table 2.
Table 23. MII Transmit AC Timing Specifications
At recommended operating conditions with LV
DDA
/LV
DDB
/NV
DD
of 3.3 V ± 0.3V.
Parameter/Condition Symbol
1
Min Typ Max Unit
TX_CLK clock period 10 Mbps t
MTX
— 400 — ns
TX_CLK clock period 100 Mbps t
MTX
—40—ns
TX_CLK duty cycle t
MTXH/
t
MTX
35 — 65 %
TX_CLK to MII data TXD[3:0], TX_ER, TX_EN delay t
MTKHDX
1515ns
TX_CLK data clock rise V
IL
(min) to V
IH
(max) t
MTXR
1.0 — 4.0 ns
TX_CLK data clock fall V
IH
(max) to V
IL
(min) t
MTXF
1.0 — 4.0 ns
Note:
1. The symbols used for timing specifications follow the pattern of t
(first two letters of functional block)(signal)(state) (reference)(state)
for
inputs and t
(first two letters of functional block)(reference)(state)(signal)(state)
for outputs. For example, t
MTKHDX
symbolizes MII transmit
timing (MT) for the time t
MTX
clock reference (K) going high (H) until data outputs (D) are invalid (X). Note that, in general,
the clock reference symbol representation is based on two to three letters representing the clock of a particular functional.
For example, the subscript of t
MTX
represents the MII(M) transmit (TX) clock. For rise and fall times, the latter convention is
used with the appropriate letter: R (rise) or F (fall).