Datasheet

411
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
• DS: Drive Strength (only for low-power SDRAM)
DS parameter is transmitted to the SDRAM during initialization to select the SDRAM strength of data output. This parame-
ter must be set according to the SDRAM device specification.
After initialization, as soon as DS field is modified and self-refresh mode is activated, the Extended Mode Register is
accessed automatically and DS bits are updated before entry in self-refresh mode. This feature is not supported when
SDRAMC shares an external bus with another controller.
• TIMEOUT: Time to define when low-power mode is enable
Values which are not listed in the table must be considered as “reserved”.
Value Name Description
00 LP_LAST_XFER
The SDRAM controller activates the SDRAM low-power mode immediately after the end
of the last transfer.
01 LP_LAST_XFER_64
The SDRAM controller activates the SDRAM low-power mode 64 clock cycles after the
end of the last transfer.
10 LP_LAST_XFER_128
The SDRAM controller activates the SDRAM low-power mode 128 clock cycles after the
end of the last transfer.