Address Space
1-5
Introduction
1.4.2
RAM
RAM starts at 0200h. The end address of RAM depends on the amount of RAM
present and varies by device. RAM can be used for both code and data.
1.4.3
Peripheral Modules
Peripheral modules are mapped into the address space. The address space
from 0100 to 01FFh is reserved for 16-bit peripheral modules. These modules
should be accessed with word instructions. If byte instructions are used, only
even addresses are permissible, and the high byte of the result is always 0.
The address space from 010h to 0FFh is reserved for 8-bit peripheral modules.
These modules should be accessed with byte instructions. Read access of
byte modules using word instructions results in unpredictable data in the high
byte. If word data is written to a byte module only the low byte is written into
the peripheral register, ignoring the high byte.
1.4.4
Special Function Registers (SFRs)
Some peripheral functions are configured in the SFRs. The SFRs are located
in the lower 16 bytes of the address space, and are organized by byte. SFRs
must be accessed using byte instructions only. See the device-specific data
sheets for applicable SFR bits.
1.4.5
Memory Organization
Bytes are located at even or odd addresses. Words are only located at even
addresses as shown in Figure 1−3. When using word instructions, only even
addresses may be used. The low byte of a word is always an even address.
The high byte is at the next odd address. For example, if a data word is located
at address xxx4h, then the low byte of that data word is located at address
xxx4h, and the high byte of that word is located at address xxx5h.
Summary of Contents for MSP430x4xx Family
Page 1: ...MSP430x4xx Family 2007 Mixed Signal Products User s Guide SLAU056G ...
Page 2: ......
Page 6: ...vi ...
Page 114: ...3 76 RISC 16 Bit CPU ...
Page 304: ...5 20 FLL Clock Module ...
Page 340: ...7 8 Supply Voltage Supervisor ...
Page 348: ...8 8 16 Bit Hardware Multiplier ...
Page 372: ...9 24 32 Bit Hardware Multiplier ...
Page 400: ...10 28 DMA Controller ...
Page 428: ...13 10 Basic Timer1 ...
Page 466: ...15 24 Timer_A ...
Page 522: ...17 30 USART Peripheral Interface UART Mode ...
Page 544: ...18 22 USART Peripheral Interface SPI Mode ...
Page 672: ...23 12 Comparator_A ...
Page 692: ...24 20 LCD Controller ...
Page 746: ...26 28 ADC12 ...