MC9S12E256 Datasheet, PDF (92/602 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
2.3.2.4 Flash Configuration Register (FCNFG)
The unbanked FCNFG register enables the Flash interrupts and gates the security backdoor writes.
R
W
Reset
7
CBEIE
0
6
5
4
3
2
0
0
0
CCIE
KEYACC
0
0
0
0
0
= Unimplemented or Reserved
Figure 2-7. Flash Configuration Register (FCNFG)
1
0
0
BKSEL
0
0
CBEIE, CCIE, KEYACC and BKSEL bits are readable and writable while all remaining bits read 0 and
are not writable. KEYACC is only writable if KEYEN (see Section 2.3.2.2, “Flash Security Register
(FSEC)”) is set to the enabled state.
Table 2-9. FCNFG Field Descriptions
Field
Description
7
CBEIE
6
CCIE
5
KEYACC
0
BKSEL
Command Buffer Empty Interrupt Enable — The CBEIE bit enables an interrupt in case of an empty command
buffer in the Flash module.
0 Command buffer empty interrupt disabled.
1 An interrupt will be requested whenever the CBEIF flag (see Section 2.3.2.7, “Flash Status Register (FSTAT)”)
is set.
Command Complete Interrupt Enable — The CCIE bit enables an interrupt in case all commands have been
completed in the Flash module.
0 Command complete interrupt disabled.
1 An interrupt will be requested whenever the CCIF flag (see Section 2.3.2.7, “Flash Status Register (FSTAT)”)
is set.
Enable Security Key Writing
0 Flash writes are interpreted as the start of a command write sequence.
1 Writes to Flash array are interpreted as keys to open the backdoor. Reads of the Flash array return invalid
data.
Block Select — The BKSEL bit indicates which register bank is active.
0 Select register bank associated with Flash block 0.
1 Select register bank associated with Flash block 1.
MC9S12E256 Data Sheet, Rev. 1.08
92
Freescale Semiconductor