Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet

SAM4S Series [DATASHEET]

Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14

476

SMC_MODE[0..3]

0x400E000C [0], 0x400E001C [1], 0x400E002C [2], 0x400E003C [3]

Read-write

1: The read operation is controlled by the NRD signal. 

– If TDF cycles are programmed, the external bus is marked busy after the rising edge of NRD. 

– If TDF optimization is enabled (TDF_MODE =1), TDF wait states are inserted after the setup of NRD.

0: The read operation is controlled by the NCS signal. 

– If TDF cycles are programmed, the external bus is marked busy after the rising edge of NCS.

– If TDF optimization is enabled (TDF_MODE =1), TDF wait states are inserted after the setup of NCS.

• WRITE_MODE 

1: The write operation is controlled by the NWE signal. 

– If TDF optimization is enabled (TDF_MODE =1), TDF wait states will be inserted after the setup of NWE.

0: The write operation is controlled by the NCS signal. 

– If TDF optimization is enabled (TDF_MODE =1), TDF wait states will be inserted after the setup of NCS.

The NWAIT signal is used to extend the current read or write signal. It is only taken into account during the pulse phase of 

the read and write controlling signal. When the use of NWAIT is enabled, at least one cycle hold duration must be pro-

grammed for the read and write controlling signal.

• Disabled Mode: The NWAIT input signal is ignored on the corresponding Chip Select.

• Frozen Mode: If asserted, the NWAIT signal freezes the current read or write cycle. After deassertion, the read/write 

cycle is resumed from the point where it was stopped.

• Ready Mode: The NWAIT signal indicates the availability of the external device at the end of the pulse of the controlling 

read or write signal, to complete the access. If high, the access normally completes. If low, the access is extended until 
NWAIT returns high. 

31

30

29

28

27

26

25

24

–

–

PS

–

–

–

PMEN

23

22

21

20

19

18

17

16

–

–

–

TDF_MODE

TDF_CYCLES

15

14

13

12

11

10

9

8

–

–

–

–

–

–

–

–

7

6

5

4

3

2

1

0

–

–

EXNW_MODE

–

–

WRITE_MODE

READ_MODE

0

DISABLED

Disabled

1

Reserved

2

FROZEN

Frozen Mode

3

READY

Ready Mode