VSC7440 datasheet(406/444 Pages) MICROSEMI

406 / 444 page

Electrical Specifications

VMDS-10492 VSC7440 Datasheet Revision 4.2

389

6.2.7

MII Management

All AC specifications for the MII Management (MIIM) interface meet or exceed the requirements of

IEEE 802.3-2002 (clause 22.2-4).

All MIIM AC timing requirements are specified relative to the input low and input high threshold levels.

The following illustration shows the MIIM waveforms and required measurement points for the signals.

Figure 136 •

MIIM Timing Diagram

The set up time of MDIO relative to the rising edge of MDC is defined as the length of time between when

the MDIO exits and remains out of the switching region and when MDC enters the switching region. The

hold time of MDIO relative to the rising edge of MDC is defined as the length of time between when MDC

exits the switching region and when MDIO enters the switching region.

The MIIM signals are GPIO alternate functions. For more information, see GPIO Overlaid Functions,

page 352. All MIIM signals comply with the specifications in the following table. The MDIO signal

requirements are requested at the pin of the device.

Table 308 •

MIIM Timing Specifications

Parameter

Symbol Minimum

Maximum

Unit

Condition

MDC frequency1

For the maximum value, the device supports an MDC clock speed of up to 20 MHz for faster communication with

the PHYs. If the standard frequency of 2.5 MHz is used, the MIIM interface is designed to meet or exceed the

IEEE 802.3 requirements of the minimum MDC high and low times of 160 ns and an MDC cycle time of minimum

400 ns, which is not possible at faster speeds.

0.488

20.83

MHz

MDC cycle time2

Calculated as tC =1/ƒ.

2048

MDC time high

tW(CH)

CL =50pF

MDC time low

tW(CL)

CL =50pF

MDIO setup time to MDC on write

tSU(W)

CL =50pF

MDIO hold time from MDC on write tH(W)

CL =50pF

MDIO setup time to MDC on read

tSU(R)

CL = 50 pF on MDC

MDIO hold time from MDC on read tH(R)

0ns

CL =50pF

tH(W)

tH(R)

VIH(DC)MIN

VIL(DC)MAX

VIH(DC)MIN

VIL(DC)MAX

VIH(DC)MIN

VIL(DC)MAX

tSU(W)

tSU(R)

tW(CL)

tW(CH)

MDC

MDIO

(Write)

MDIO

(Read)

VSC7440 Datasheet(PDF) 406 Page - Microsemi Corporation

VSC7440 Datasheet(HTML) 406 Page - Microsemi Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL