C2510Fx / CC2511Fx
The steps required to perform a flash page
erase from within flash memory are outlined in
Figure 24.
Note: If flash erase operations are
performed from within flash memory and
the watchdog timer is enabled, a watchdog
timer interval must be selected that is
longer than 20 ms, the duration of the flash
page erase operation, so that the CPU will
manage to clear the watchdog timer.
Note that, while executing program code from
within flash memory, when a flash erase or
write operation is initiated, program execution
will resume from the next instruction when the
Flash Controller has completed the operation.
The flash erase operation requires that the
instruction that starts the erase i.e. writing to
FCTL.ERASE is followed by a NOP instruction
as shown in the example code. Omitting the
NOP instruction after the flash erase operation
will lead to undefined behavior.
; Erase page 1 in flash memory
; Assumes 26 MHz system clock is used
;
CLR
MOV
JB
MOV
MOV
MOV
NOP
RET
EA
A,FCTL
ACC.7,C1
FADDRH,#02h
FWT,#2Ah
FCTL,#01h
; Mask interrupts
; Wait until flash controller is ready
C1:
; Setup flash address (FADDRH[5:1] = 1)
; Setup flash timing
; Erase page
; Must always execute a NOP after erase
; Continues here when flash is ready
Figure 24: Flash Page Erase Performed from Flash Memory
13.3.4 Flash DMA trigger
The value used for FWT.FWT[5:0]is given by
the following equation:
When the DMA channel is armed and the
FLASH trigger selected TRIG[4:0]=10010,
starting a flash write by setting FCTL.WRITE
to 1 will trigger the first DMA transfer. The
following DMA transfers will be triggered by
the Flash Controller when the Flash Write
Data register, FWDATA, is ready to receive new
data.
21000 ∗ F
FWT =
16*109
where F is the system clock frequency. The
initial value held in FWT.FWT[5:0] after a
reset is 0x11, which corresponds to 13 MHz
system clock frequency (calibrated HS
RCOSC frequency for CC2510Fx when using a
26 MHz XOSC).
13.3.5 Flash Write Timing
The Flash Controller contains
a
timing
13.3.6 Flash Controller Registers
generator, which controls the timing sequence
of flash write and erase operations. The timing
generator uses the information set in the Flash
Write Timing register, FWT.FWT[5:0], to set
the internal timing. FWT.FWT[5:0] must be
set to a value according to the currently
selected system clock frequency.
The Flash Controller registers are described in
this section.
SWRS055D
Page 86 of 243
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