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

Product codes
ATSAM4S-WPIR-RD
Page of 1231
451
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
Figure 26-11. WRITE_MODE = 1. The write operation is controlled by NWE 
26.8.4.2 Write is Controlled by NCS (WRITE_MODE = 0)
 shows the waveforms of a write operation with WRITE_MODE set to 0. The data is put on the bus 
during the pulse and hold steps of the NCS signal. The internal data buffers are switched to output mode after the 
NCS_WR_SETUP time, and until the end of the write cycle, regardless of the programmed waveform on NWE.
Figure 26-12. WRITE_MODE = 0. The write operation is controlled by NCS
26.8.5 Write Protected Registers
To prevent any single software error that may corrupt SMC behavior, the registers listed below can be write-
protected by setting the WPEN bit in the SMC Write Protect Mode Register (SMC_WPMR).
If a write access in a write-protected register is detected, then the WPVS flag in the SMC Write Protect Status 
Register (SMC_WPSR) is set and the field WPVSRC indicates in which register the write access has been 
attempted.
The WPVS flag is automatically reset after reading the SMC Write Protect Status Register (SMC_WPSR).
List of the write-protected registers:
MCK
D[7:0]
NCS
A[23:0]
NWE  
MCK
D[7:0]
NCS
NWE 
A[23:0]