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DDR_CLK
DDR_CKE
DDR_CS
DDR_RAS
DDR_CAS
DDR_WE
DDR_A[13:0]
DDR_BA[2:0]
DDR_DQM[1:0]
RFR
DDR_CLK
Architecture
374
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
DDR2/mDDR Memory Controller
14.2.3.1 Refresh Mode
The DDR2/mDDR memory controller issues refresh commands to the DDR2/mDDR SDRAM memory
(
). REFR is automatically preceded by a DCAB command, ensuring the deactivation of all CE
spaces and banks selected. Following the DCAB command, the DDR2/mDDR memory controller begins
performing refreshes at a rate defined by the refresh rate (RR) bit in the SDRAM refresh control register
(SDRCR). Page information is always invalid before and after a REFR command; thus, a refresh cycle
always forces a page miss. This type of refresh cycle is often called autorefresh. Autorefresh commands
may not be disabled within the DDR2/mDDR memory controller. See
for more details on
REFR command scheduling.
Figure 14-4. Refresh Command