M e m o r y C o n t r o l l e r M o d u l e

BSIZE

Burst length

 

 

11

Full page

 

 

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:

1Set BSIZE to full page.

2Read the address within the range of the chip select.

3Set 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.

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

The load mode command is issued after at least one memory read cycle has been executed to the SDRAM device.

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Digi NS7520 manual Sdram Mode register settings, Full, Address Field Value