LM3S9B81 Datasheet, PDF (204/1155 Pages) Texas Instruments – Stellaris® LM3S9B81 Microcontroller

Internal Memory
Caution – The Flash memory is divided into sectors of electrically separated address ranges of 4 KB
each, aligned on 4 KB boundaries. Erase/program operations on a 1-KB page have an electrical effect
on the other three 1-KB pages within the sector. A specific 1-KB page must be erased after 6 total
erase/program cycles occur to the other pages within it’s 4-KB sector. The following sequence of
operations on a 4-KB sector of Flash memory (Page 0..3) provides an example:
■ Page 3 is erase and programmed with values.
■ Page 0, Page 1, and Page 2 are erased and then programmed with values. At this point Page 3 has
been affected by 3 erase/program cycles.
■ Page 0, Page 1, and Page 2 are again erased and then programmed with values. At this point Page
3 has been affected by 6 erase/program cycles.
■ If the contents of Page 3 must continue to be valid, Page 3 must be erased and reprogrammed before
any other page in this sector has another erase or program operation.
7.3.1.1
To program a 32-bit word
1. Write source data to the FMD register.
2. Write the target address to the FMA register.
3. Write the Flash memory write key and the WRITE bit (a value of 0xA442.0001) to the FMC
register.
4. Poll the FMC register until the WRITE bit is cleared.
Important: To ensure proper operation, two writes to the same word must be separated by an
ERASE. The following two sequences are allowed:
■ ERASE -> PROGRAM value -> PROGRAM 0x0000.0000
■ ERASE -> PROGRAM value -> ERASE
The following sequence is NOT allowed:
■ ERASE -> PROGRAM value -> PROGRAM value
7.3.1.2
7.3.1.3
To perform an erase of a 1-KB page
1. Write the page address to the FMA register.
2. Write the Flash memory write key and the ERASE bit (a value of 0xA442.0002) to the FMC
register.
3. Poll the FMC register until the ERASE bit is cleared.
To perform a mass erase of the Flash memory
1. Write the Flash memory write key and the MERASE bit (a value of 0xA442.0004) to the FMC
register.
204
June 29, 2010
Texas Instruments-Advance Information