NXP Semiconductors UM10237 8. MAM usage notes

UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 106 o f 792
NXP Semiconductors UM10237
Chapter 6: LPC24XX Memory Accelerator Module (MAM)
8. MAM usage notes
When changing MAM timing, the MAM must first be turned off by writing a zero to
MAMCR. A new value may then be written to MAMTIM. Finally, the MAM may be turned
on again by writing a value (1 or 2) corresponding to the desired operating mode to
MAMCR.
For a system clock slower than 20 MHz, MAMTIM can be 001. For a system clock
between 20 MHz and 40 MHz, flash access time is suggested to be 2 CCLKs, while in
systems with a system clock faster than 40 MHz, 3 CCLKs are proposed. For system
clocks of 60 MHz and above, 4CCLK’s are needed.
Fig 21. Block diagram of the Memory Accelerator Module
xFFE0 xFFE4 xFFE8 xFFEC
30000 30004 30008 3000C
20000 20004 20008 2000C
10000 10004 10008 1000C
0FFF0 0FFF4 0FFF8 0FFFC
00020 00024 00028 0002C
00010 00014 00018 0001C
00000 00004 00008 0000C
INCREMENTOR
MUX DQ
EN
ENAL0
cclk
ADDR
=
EQA0
ADDR PREFETCH LATCH ADDR BT LATCH ADDR DATA LATCH
DATA MUXBT MUXPREFETCH MUX
= = =
FINAL MUX
ENP ENBT END
EQPREF EQBT EQD
LA[3:2]
DI[31:0] (to ARM core)
32 32 32
128 128 128
128
[18:4]