SAM3SD8C Atmel Corporation, SAM3SD8C Datasheet - Page 394

• Manufacturer Part Number: SAM3SD8C
• Manufacturer: Atmel Corporation

23.10.3.1
23.10.3.2
23.10.4
394
394
SAM3S8/SD8
SAM3S8/SD8
Read to Write Wait State
User Procedure
Slow Clock Mode Transition
When detecting that a new user configuration has been written in the user interface, the SMC
inserts a wait state before starting the next access. The so called “Reload User Configuration
Wait State” is used by the SMC to load the new set of parameters to apply to next accesses.
The Reload Configuration Wait State is not applied in addition to the Chip Select Wait State. If
accesses before and after re-programming the user interface are made to different devices
(Chip Selects), then one single Chip Select Wait State is applied.
On the other hand, if accesses before and after writing the user interface are made to the same
device, a Reload Configuration Wait State is inserted, even if the change does not concern the
current Chip Select.
To insert a Reload Configuration Wait State, the SMC detects a write access to any
SMC_MODE register of the user interface. If the user only modifies timing registers
(SMC_SETUP, SMC_PULSE, SMC_CYCLE registers) in the user interface, he must validate
the modification by writing the SMC_MODE, even if no change was made on the mode
parameters.
The user must not change the configuration parameters of an SMC Chip Select (Setup, Pulse,
Cycle, Mode) if accesses are performed on this CS during the modification. Any change of the
Chip Select parameters, while fetching the code from a memory connected on this CS, may lead
to unpredictable behavior. The instructions used to modify the parameters of an SMC Chip
Select can be executed from the internal RAM or from a memory connected to another CS.
A Reload Configuration Wait State is also inserted when the Slow Clock Mode is entered or
exited, after the end of the current transfer (see
Due to an internal mechanism, a wait cycle is always inserted between consecutive read and
write SMC accesses.
This wait cycle is referred to as a read to write wait state in this document.
This wait cycle is applied in addition to chip select and reload user configuration wait states
when they are to be inserted. See
Figure 23-13 on page
“Slow Clock Mode” on page
391.
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12
405).