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6237A–DRMSD–29-May-06

ATSAM3703

Command Sequencing

The ATSAM3703 supports DDR200 and faster DDR devices, and thus the DDR device must

support parameters defined in Table 9-5.

ATSAM3703 to DDR

DDR to ATSAM3703

The data from DDR to ATSAM3703 must meet timing requirements defined in Table 9-7. These

parameters are applicable at input of ATSAM3703, and must include effects of DDR device and

effects of board layout.

Table 9-5.

Supported Parameters

Symbol

Parameter

Value

t

MRD

MODE REGISTER SET command cycle time

min 20 ns

t

RAS

ACTIVE to PRECHARGE command

min 50 ns

max 70 us

t

RC

ACTIVE to ACTIVE/AUTO REFRESH command period

min 70 ns

t

RFC

AUTO REFRESH to ACTIVE/AUTO REFRESH command

period

min 120 ns

t

RCD

ACTIVE to READ or WRITE delay

min 20 ns

PRECHARGE command period

min 20 ns

ACTIVE bank a to ACTIVE bank b command

min 20 ns

t

WR

WRITE recovery time

min 20 ns

Internal WRITE to READ command delay

min 10 ns

Exit self refresh to non-READ command

min 80 ns

t

XSRD

Exit self refresh to READ command

min 2 us

Average periodic REFRESH interval

7.8 us

Table 9-6.

Parameters

Symbol

Parameter

Value

t

IH

Address and control hold time

min 3.6 ns

Address and control setup time

min 3.2 ns

t

DSS

DQS falling edge to CK setup time

min 4.3 ns

t

DSH

DQS falling edge hold time from CK

min 4.3 ns

DQ and DM setup time

min 1.7 ns

t

DH

DQ and DM hold time

min 0.8 ns