ADUC702 AD [Analog Devices], ADUC702 Datasheet - Page 21

• Manufacturer Part Number: ADUC702
• Description: Precision Analog Microcontroller 12-bit Analog I/O, ARM7TDMI MCU
• Manufacturer: AD [Analog Devices]

Preliminary Technical Data
MEMORY ORGANISATION
The part incorporates two separate blocks of memory, 8kByte of
SRAM and 64kByte of On-Chip Flash/EE memory. 62kByte of
On-Chip Flash/EE memory are available to the user, and the
remaining 2kBytes are reserved for the factory configured boot
page. These two blocks are mapped as shown in
Figure 4
Note that by default, after a reset, the Flash/EE memory is
mirrored at address 0x00000000. It is possible to remap the
SRAM at address 0x00000000 by clearing bit 0 of the REMAP
MMR. This remap function is described in more details in the
Flash/EE memory chapter.
Memory Access
The ARM7 core sees memory as a linear array of 2 32 byte
location where the different blocks of memory are mapped as
outlined in
Figure 4
The ADuC702x memory organisation is configured in little
endian format: the least significant byte is located in the lowest
byte address and the most significant byte in the highest byte
address.
FFFF0000h
00080000h
00010000h
00000000h
.
.
bit31
Byte3
FFFFFFFFh
0000FFFFh
0008FFFFh
00011FFFh
B
7
3
Byte2
Figure 4: Physical memory map
A
6
2
Figure 5: little endian format
MMRs
Reserved
Flash/EE
Reserved
SRAM
Re-mappable Memory Space
(Flash/EE or SRAM)
32 bits
Byte1
9
5
1
Byte0
8
4
0
bit0
0xFFFFFFFFh
0x00000004h
0x00000000h
Rev. PrB | Page 21 of 80
Flash/EE Memory
The total 64kBytes of Flash/EE are organised as 32k X 16 bits.
31k X 16 bits are user space and 1k X 16 bits is reserved for the
on chip kernel. The page size of this Flash/EE memory is
512Bytes.
62kBytes of Flash/EE are available to the user as code and non-
volatile data memory. There is no distinction between data and
program as ARM code shares the same space. The real width of
the Flash/EE memory is 16 bits, which means that in ARM
mode (32-bit instruction), two accesses to the Flash/EE are
necessary
recommended to use Thumb mode when executing from
Flash/EE memory for optimum access speed. The maximum
access speed for the Flash/EE memory is 45MHz in Thumb
mode and 22.5MHz in full ARM mode. More details on
Flash/EE access time are outlined later in ‘Execution from
SRAM and Flash/EE’ section of this datasheet.
SRAM
8kBytes of SRAM are available to the user, organized as 2k X 32
bits, i.e. 2kWords. ARM code can run directly from SRAM at
45MHz , given that the SRAM array is configured as a 32-bit
wide memory array. More details on SRAM access time are
outlined later in ‘Execution from SRAM and Flash/EE’ section
of this datasheet.
Memory Mapped Registers
The Memory Mapped Register (MMR) space is mapped into
the upper 2 pages of the memory array and accessed by indirect
addressing through the ARM7 banked registers.
The MMR space provides an interface between the CPU and all
on-chip peripherals. All registers except the core registers
reside in the MMR area. All shaded locations shown in Figure 6
are unoccupied or reserved locations and should not be
accessed by user software. Table 6 shows a full MMR memory
map.
for each instruction fetch. It is therefore
ADuC702x Series