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119
Memory Controller Module
The JEDEC SDRAM standard requires the SDRAM load mode command to set burst
length to
full page to recognize burst terminate commands. Not all SDRAMs require
this setting. If you want to set burst length to a value other than
full page, follow
these steps:
1 Set BSIZE to full page.
2 Read the address within the range of the chip select.
3 Set BSIZE to the value you want to use.
The load mode command is issued as part of the first memory read cycle loading
full
page
into the SDRAM Control register. The load mode command is executed only on
the first memory cycle following power reset.
SDRAM Mode register
The SDRAM Mode register is loaded during the first memory cycle to the SDRAM device
after the V bit is set to 1 in the Chip Select Base Address register. The MEM module
loads the SDRAM Mode register with the values shown in Table 46.
The load mode command is issued after at least one memory read cycle has been
executed to the SDRAM device.
11 Full page
BSIZE Burst length
Address Field Value
11:9 Write burst mode 001 - Single location access
8:7 Operating mode 00 - Standard operation
6:4 CAS latency BCYC + 1
3 Burst type 0 - Sequential
2:0 Burst length See "BSIZE configuration" on page 118.
Table 46: SDRAM Mode register settings