Hardware Reference
In-Depth Information
7
6
5
4
3
2
1
0
CBEIE
CCIE
KEYACC
0
0
0
BKSEL1
BKSEL0
base+$103
Reset:
0
0
0
0
0
0
0
0
CBEIE: command buffer empty interrupt enable
0 = command buffer empty interrupts disabled.
1 = an interrupt will be requested whenever the CBEIF flag is set.
CCIE: command completion interrupt enable
0 = command complete interrupts disabled.
1 = an interrupt will be requested whenever the CCIF flag is set.
KEYACC: enable security key writing
0 = flash writes are interpreted as the start of a program or erase sequence.
1 = writes to flash array are interpreted as keys to open the backdoor. Reads
of the flash array return invalid data.
BKSEL[1:0]: register bank select
00 = flash 0.
01 = flash 1.
10 = flash 2.
11 = flash 3.
Figure 14.13
■
Flash configuration register (FCNFG)
7
6
5
4
3
2
1
0
CBEIF
CCIF
PVOL
ACCERR
0
BLANK
0
0
base+$105
Reset:
1
1
0
0
0
0
0
0
CBEIF: command buffer empty interrupt flag
0 = command buffers are full.
1 = command buffers are ready to accept a new command.
CCIF: command completion interrupt flag
0 = command in progress.
1 = all commands are completed.
PVOL: protection violation
0 = no protection violation has occurred.
1 = a protection violation has occurred.
ACCERR: flash access error
0 = no failure.
1 = access error has occurred.
BLANK: array has been verified as erased.
0 = if an erase and verify command has been requested, and the CCIF flag is set,
then a zero in BLANK indicates that the block is not erased.
1 = flash block verifies as erased.
Figure 14.14
■
Flash status register (FSTAT)
The CBEIF flag indicates that the address, data, and command buffers are empty so that a
new command sequence can be started. The CBEIF flag is cleared by writing a 1 to it. Writing a
0 to the CBEIF flag has no effect on CBEIF but sets ACCERR, which can be used to abort a com-
mand sequence.
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