UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
17 of 362
NXP Semiconductors
UM10208
Chapter 4: LPC2800 Cache
, page 2 of the lower 32 megabytes of address space has been mapped to
an address in the external static memory space by placing a value of 0x104 in the
PAGE_ADDRESS_2 register. Details of this remapping may be found in the descriptions
of the PAGE_ADDRESS registers later in this chapter.
When re-mapping points to a higher page in the memory map, that page may still also be
accessed directly by the CPU using the original absolute address of the page. In that
case, the cache takes no part in the access. This allows both cached and non-cached
access to the same address region if needed.
Each of the 16 configurable cache pages can be individually enabled and disabled, as
well as having a virtual address programmed.
Fig 5.
Memory mapping
0x0000_0000
0x0020_0000
0x0040_0000
0x0200_0000
Page 0
Page 1
Page 2
Page 16
First
32 M
bytes
Above
32 M
bytes
External
SRAM
0x0000_0000
0x0200_0000
Memory
(address as seen
by the AHB bus)
First
32 M
bytes
Above
32 M
bytes
Memory
(address as issued
by the CPU)
0x0040_0000
0x2080_0000
External
SRAM
0x2080_0000
Address remapped
by value in
ADDRESS_PAGE_2