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MSP430x11x1
MIXED SIGNAL MICROCONTROLLER
SLAS241C – SEPTEMBER 1999 – REVISED JUNE 2000
15
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
flash memory control register FCTL3 (continued)
BUSY 012Ch, bit0,
The BUSY bit shows if an access to the flash memory is allowed (BUSY=0), or
if an access violation occurs. The BUSY bit is read-only, but a write operation is
allowed. The BUSY bit should be tested before each write and erase cycle. The
flash timing-generator hardware immediately sets the BUSY bit after start of a
write, segment-write, erase, or
mass
erase operation. If the timing generator has
completed the operation, the BUSY bit is reset by the hardware.
No program code can be executed from the
busy
flash memory during the entire
program or erase cycle.
0: Flash memory is not busy.
1: Flash memory is busy, and remains in busy state if segment write function
is in
wait
mode.
KEYV, 012Ch, bit1
Key violation
0: Key 0A5h (high byte) was not violated.
1: Key 0A5h (high byte) was violated. Violation occurs when a write access to
registers FCTL1, FCTL2, or FCTL3 is executed and the
high byte
is not
equal to 0A5h. If the security key is violated, bit KEYV is set and a PUC is
performed.
ACCVIFG, 012Ch, bit2 Access violation interrupt flag
The access-violation flag is set when any combination of control bits other than
those shown in Table 3 is attempted, or an instruction is fetched while a
segment-write operation is active.
Reading the control registers will not set the ACCVIFG bit.
NOTE: The respective interrupt-enable bit ACCVIE is located in the interrupt
enable register IE1 in the special function register. The software can set
the ACCVIFG bit. If set by software, an NMI is also executed.
WAIT, 012CH, bit3
In the segment-write mode, the WAIT bit indicates that data has been written and
the flash memory is prepared to receive the next data for programming. The
WAIT bit is read only, but a write to the WAIT bit is allowed.
0: The segment-write operation has began and programming is in progress.
1: The segment-write operation is active and data programming is complete.