Atmel SAM9X25, Manual

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11054A–ATARM–27-Jul-11
SAM9X25
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11054A–ATARM–27-Jul-11
SAM9X25
Figure 29-15. WRITE_MODE = 0. The write operation is controlled by NCS
29.9.5 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:
• Section 29.16.1 ”SMC Setup Register”
• Section 29.16.2 ”SMC Pulse Register”
• Section 29.16.3 ”SMC Cycle Register”
• Section 29.16.4 ”SMC MODE Register”
• Section 29.16.5 ”SMC DELAY I/O Register”
29.9.6 Coding Timing Parameters
All timing parameters are defined for one chip select and are grouped together in one
SMC_REGISTER according to their type.
The SMC_SETUP register groups the definition of all setup parameters:
• NRD_SETUP, NCS_RD_SETUP, NWE_SETUP, NCS_WR_SETUP
The SMC_PULSE register groups the definition of all pulse parameters:
• NRD_PULSE, NCS_RD_PULSE, NWE_PULSE, NCS_WR_PULSE
The SMC_CYCLE register groups the definition of all cycle parameters:
• NRD_CYCLE, NWE_CYCLE
MCK
D[31:0]
NCS
NWE,
NWR0, NWR1,
NWR2, NWR3
A
[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1