Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Datenbogen

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SAM9M10 [DATASHEET]

6355F–ATARM–12-Mar-13

Programming null pulse is not permitted. Pulse must be at least set to 1. A null value leads to unpredictable
behavior.

As NCS and NRD waveforms are defined independently of one other, the SMC needs to know when the read data
is available on the data bus. The SMC does not compare NCS and NRD timings to know which signal rises first.
The READ_MODE parameter in the SMC_MODE register of the corresponding chip select indicates which signal
of NRD and NCS controls the read operation.

t

PACC

 after the falling edge of NRD, and turns to ‘Z’ after the rising edge of NRD. In this case, the READ_MODE

must be set to 1 (read is controlled by NRD), to indicate that data is available with the rising edge of NRD. The
SMC samples the read data internally on the rising edge of Master Clock that generates the rising edge of NRD,
whatever the programmed waveform of NCS may be.

READ_MODE = 1: Data is sampled by SMC before the rising edge of NRD

PACC 

after the falling edge of

the NCS signal and remains valid until the rising edge of NCS. Data must be sampled when NCS is raised. In that
case, the READ_MODE must be set to 0 (read is controlled by NCS): the SMC internally samples the data on the
rising edge of Master Clock that generates the rising edge of NCS, whatever the programmed waveform of NRD
may be.

Data Sampling

t

PACC

MCK

A[25:2]

NBS0,NBS1,
NBS2,NBS3,
A0, A1

NCS

NRD

D[31:0]