Texas Instruments AM18x evaluation module with Wi-Fi TMDXEVMWIFI1808L TMDXEVMWIFI1808L Datenbogen

Produktcode

TMDXEVMWIFI1808L

AM1808

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SPRS653E – FEBRUARY 2010 – REVISED MARCH 2014

6.11.3.8 Net Classes

Table 6-27

lists the clock net classes for the DDR2/mDDR interface.

Table 6-28

lists the signal net

classes, and associated clock net classes, for the signals in the DDR2/mDDR interface. These net classes
are used for the termination and routing rules that follow.

Table 6-27. Clock Net Class Definitions

CLOCK NET CLASS

PIN NAMES

DDR_CLKP / DDR_CLKN

DQS0

DDR_DQS[0]

DQS1

DDR_DQS[1]

Table 6-28. Signal Net Class Definitions

ASSOCIATED CLOCK

SIGNAL NET CLASS

NET CLASS

PIN NAMES

ADDR_CTRL

DDR_BA[2:0], DDR_A[13:0], DDR_CS, DDR_CAS, DDR_RAS, DDR_WE,
DDR_CKE

DQS0

DDR_D[7:0], DDR_DQM0

DQS1

DDR_D[15:8], DDR_DQM1

DQGATE

CK, DQS0, DQS1

DDR_DQGATE0, DDR_DQGATE1

6.11.3.9 DDR2/mDDR Signal Termination

No terminations of any kind are required in order to meet signal integrity and overshoot requirements.
Serial terminators are permitted, if desired, to reduce EMI risk; however, serial terminations are the only
type permitted.

Table 6-29

shows the specifications for the series terminators.

Table 6-29. DDR2/mDDR Signal Terminations

(1) (2) (3)

NO.

PARAMETER

MIN

TYP

MAX

UNIT

CK Net Class

ADDR_CTRL Net Class

Data Byte Net Classes (DQS[0], DQS[1], D0, D1)

(4)

DQGATE Net Class (DQGATE)

(1)

Only series termination is permitted, parallel or SST specifically disallowed.

(2)

Terminator values larger than typical only recommended to address EMI issues.

(3)

Termination value should be uniform across net class.

(4)

When no termination is used on data lines (0

Ω), the DDR2/mDDR devices must be programmed to operate in 60% strength mode.

Peripheral Information and Electrical Specifications

117

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