SH33F2801PSLASH032PR datasheet(33/407 Pages) SINOWEALTH

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SH33F2801

8.3.3.6

Main Program Block Programming

The Flash operation provides a 32-bit word/16-bit half-word programming function to modify the contents of the flash

main memory block. To program on main flash program block, 32 bits/16 bits can be written each time. The addresses must

be aligned by 32 bits/16 bits. If they are not aligned, the corresponding operation is invalid and the relevant error flag is set

to 1. When the FLASH_CR register operation instruction word is set to main program block programming, writing a word or

half word at a flash address will initiate a programming. During the programming process (bit BSY@FLASH_SR bit is '1'),

any operation that reads or writes to flash will cause CPU to pause until the end of this flash programming.

The following steps show the procedure of word programming operation register.

(a) Single word or half-word programming

(1) Unlock Flash main block by writing the correct sequence of keys into FLASH_KEYR, and check that

MNLCK@FLASH_CR is cleared.

(2) Check that no Flash memory operation is ongoing by checking the BSY bit in the FLASH_SR register.

(3) When the BSY@FLASH_SR bit is cleared, write the flash main program block command (MPG) word and program

operation width selection bit to the FLASH_CR register. (4) Set STRT@FLASH_CR bit.

(5) Write a 32-bit word/16-bit half-word into the desired address.

(6) Check BSY@FLASH_SR bit to determine whether the programming instruction has been executed.

(7) The operation is done when BSY@FLASH_SR bit is cleared.

The operation flowchart is as follows:

Figure8-7

Main Program Block Programming (Single Word or Half-word)

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