UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
467 of 1269
NXP Semiconductors
UM10503
Chapter 21: LPC43xx External Memory Controller (EMC)
•
Program the SDRAM Delay value for the EMC_CLKn lines in the EMCDELAYCLK
register in the SCU block. (See
.). Add the SDRAM delay for most
SDRAM devices running at frequencies above 96 MHz under typical conditions. Add
the SDRAM delay at any frequency to compensate for variations over temperature.
For details, see the
LPC4350_30_20_10 data sheet.
21.3 Features
•
8-bit, 16-bit, and 32-bit wide static memory support with up to four chip selects.
•
Asynchronous static memory device support including RAM, ROM, and NOR Flash,
with or without asynchronous page mode.
•
Static memory features include:
–
Asynchronous page mode read
–
Programmable wait states
–
Bus turnaround delay
–
Output enable and write enable delays
–
Extended wait
•
16-bit and 32-bit wide chip select SDRAM memory support with up to four chip selects
and up to 256 MB of data.
•
Controller supports 2 kbit, 4 kbit, and 8 kbit row address synchronous memory parts.
That is typical 512 MB, 256 MB, and 128 MB parts, with 4, 8, 16, or 32 data bits per
device.
•
Dynamic memory interface support including Single Data Rate SDRAM.
•
Dynamic memory self-refresh mode controlled by software.
•
Power-saving modes dynamically control EMC_CKEOUT and EMC_CLK to
SDRAMs.
•
Low transaction latency.
Table 350. EMC clocking and power control
Base clock
Branch clock
Operating
frequency
Notes
EMC
registers
and EMC
CCLK
BASE_M4_CLK
CLK_M4_EMC
up to
204 MHz
The maximum operating
frequency depends on
temperature and voltage
settings and is typically
120 MHz for SDRAM
devices. For details, see
the
LPC4350_30_20_10
data sheet.
EMC CCLK
(divided
clock)
BASE_M4_CLK
CLK_M4_EMC_DIV
up to
204 MHz
This is an alternative
clock option for CCLK.
This clock can run at the
same frequency as
BASE_M4_CLK or half
the frequency of
BASE_M4_CLK.