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2016-04-28 - Giant Gecko Family - d0053_Rev1.20
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Note
The MSC_WDATA and MSC_ADDRB registers are not retained when entering EM2 or
lower energy modes.
7.3.5.1 Double-Word Writes
EFM32GG devices have the ability to do double writes to the flash. This is enabled by setting WDOUBLE
in MSC_WRITECTRL, and only has effect on the main pages of the flash. When double writes
are enabled, MSC_WDATA accepts two words before a flash write is started. This is signaled by
WDATAREADY in MSC_STATUS going high again after the first word is written. When the second word
is written, the actual write begins.
7.3.5.2 Low-Power Erase
Because of the fast flash in EFM32GG these devices consume approximately twice the amount of current
while doing erase operations when compared to other EFM32 devices. To limit the maximum erase
current, the erase operation can be slowed down. Set LPERASE in MSC_WRITECTRL to double the
erase time, halving the erase current.
7.3.5.3 Low-Power Write
The maximum write current can also be limited, by slowing down write operations by setting LPWRITE in
MSC_WRITECTRL. For single-word writes, this has no effect on write time, but for consecutive writes,
the write-time doubles. LPWRITE cannot be set while WDOUBLE is set.
7.3.5.4 Read-While-Write
Reading from the lower half of the flash is possible while writing/erasing from the upper half of the flash
and vice versa. Enable read-while-write by setting RWWEN in MSC_WRITECTRL.
The information pages can be written and erased while running code from the lower half of the flash.
7.3.5.5 Mass erase
A mass erase can be initiated from software using ERASEMAIN0 and ERASEMAIN1 in
MSC_WRITECMD. These commands will start a masserase on the lower and upper half of the flash
respectively. Prior to initiating a mass erase, MSC_MASSLOCK must be unlocked by writing 0x631A
to it. After a mass erase has been started, this register can be locked again to prevent runaway code
from accidentally triggering a mass erase.
The regular flash page lock bits will not prevent a mass erase. To prevent software from initiating mass
erases, use the mass erase lock bits in the mass erase lock word (MLW).
Summary of Contents for Giant Gecko EFM32GG
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