LM3S2139 Luminary Micro, Inc, LM3S2139 Datasheet - Page 116

• Manufacturer Part Number: LM3S2139
• Description: Lm3s2139 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

Internal Memory
7
7.1
7.2
7.2.1
116
Internal Memory
The LM3S2139 microcontroller comes with 16 KB of bit-banded SRAM and 64 KB of flash memory.
The flash controller provides a user-friendly interface, making flash programming a simple task.
Flash protection can be applied to the flash memory on a 2-KB block basis.
Block Diagram
Figure 7-1 on page 116 illustrates the Flash functions. The dashed boxes in the figure indicate
registers residing in the System Control module rather than the Flash Control module.
Figure 7-1. Flash Block Diagram
Functional Description
This section describes the functionality of the SRAM and Flash memories.
SRAM Memory
The internal SRAM of the Stellaris
map. To reduce the number of time consuming read-modify-write (RMW) operations, ARM has
introduced bit-banding technology in the Cortex-M3 processor. With a bit-band-enabled processor,
certain regions in the memory map (SRAM and peripheral space) can use address aliases to access
individual bits in a single, atomic operation.
The bit-band alias is calculated by using the formula:
bit-band alias = bit-band base + (byte offset * 32) + (bit number * 4)
For example, if bit 3 at address 0x2000.1000 is to be modified, the bit-band alias is calculated as:
SRAM Array
Cortex-M3
Bridge
Icode Bus
Dcode Bus
®
devices is located at address 0x2000.0000 of the device memory
Preliminary
Flash Protection
User Registers
Flash Control
Flash Timing
USER_REG1
USER_REG0
USER_DBG
FMPREn
FMPPEn
USECRL
FCMISC
FCRIS
FCIM
FMD
FMC
FMA
Flash Array
July 25, 2008