OM11077 NXP Semiconductors, OM11077 Datasheet - Page 82

• Manufacturer Part Number: OM11077
• Description: MODULE DIMM LPC2478 ARM7
• Manufacturer: NXP Semiconductors

Specifications of OM11077

• Accessory Type: Module Card
• For Use With/related Products: ARM-57TS-LPC2478
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 568-4742

NXP Semiconductors
UM10237_4
User manual
10.6 Dynamic Memory Read Configuration register
10.7 Dynamic Memory Percentage Command Period register
(EMCDynamicReadConfig - 0xFFE0 8028)
The EMCDynamicReadConfig register configures the dynamic memory read strategy.
This register must only be modified during system initialization. This register is accessed
with one wait state.
Note: This register is used for all four dynamic memory chip selects. Therefore the worst
case value for all of the chip selects must be programmed.
Important: Especially it should be highlighted that the default clock delay methodology
requires the output clock to be delayed externally to the chip to avoid hold time issue for
the SDRAM. In most application boards, there will be no such external delay circuit and
the application should write correct value to the EMCDynamicReadConfig register to use
Command Delay Strategy. The Clock Delay Strategy is the default setting on reset!
Table 5–73
Table 73.
(EMCDynamictRP - 0xFFE0 8030)
The EMCDynamicTRP register enables you to program the precharge command period,
tRP. This register must only be modified during system initialization. This value is normally
found in SDRAM data sheets as tRP. This register is accessed with one wait state.
Note: This register is used for all four dynamic memory chip selects. Therefore the worst
case value for all of the chip selects must be programmed.
Table 5–74
Bit
1:0
31:2
Symbol
Read data
strategy (RD)
-
Dynamic Memory Read Configuration register (EMCDynamicReadConfig -
address 0xFFE0 8028) bit description
shows the bit assignments for the EMCDynamicReadConfig register.
shows the bit assignments for the EMCDynamicTRP register.
Rev. 04 — 26 August 2009
Value Description
00
01
10
11
-
Chapter 5: LPC24XX External Memory Controller (EMC)
Clock out delayed strategy, using CLKOUT (command
not delayed, clock out delayed). POR reset value.
Command delayed strategy, using EMCCLKDELAY
(command delayed, clock out not delayed).
Command delayed strategy plus one clock cycle, using
EMCCLKDELAY (command delayed, clock out not
delayed).
Command delayed strategy plus two clock cycles, using
EMCCLKDELAY (command delayed, clock out not
delayed).
Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
UM10237
© NXP B.V. 2009. All rights reserved.
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Reset
Value
0x0
NA