Atmel AVR XMEGA AU series, Manual

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348
8331B–AVR–03/12
Atmel AVR XMEGA AU
27.10.3 REFRESH – SDRAM Refresh Period Register
• Bit 15:10 – Reserved
These bits are unused and reserved for future use.
• Bit 9:0 – REFRESH[9:0]: SDRAM Refresh Period
This register sets the refresh period as a number of Clk
PER2
cycles. If the EBI is busy with
another external memory access at time of refresh, up to 4 refresh will be remembered and
given at the first available time.
27.10.4 INITDLY – SDRAM Initialization Delay register
• Bit 15:14 – Reserved
These bits are unused and reserved for future use.
Table 27-14. SDRAM column bits.
SDCOL[1:0] Group Configuration Description
00 8BIT 8 column bits
01 9BIT 9 column bits
10 10BIT 10 column bits
11 11BIT 11 column bits
Bit 7 6 5 4 3 2 1 0
+0x04 REFRESH[7:0] REFRESHL
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value
0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
+0x05 – – – – – – REFRESH[9-8] REFRESHH
Read/Write R R R R R R R/W R/W
Initial Value
0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
+0x06 INITDLY[7:0] INTDLYL
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value
0 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
+0x07 – – INITDLY[13-8] INITDLYH
Read/Write R R R/W R/W R/W R/W R/W R/W
Initial Value
0 0 0 0 0 0 0 0