User Manual
214
Rev. 1.1
2019-03-18
TLE984xQX
Microcontroller with LIN and Power Switches for Automotive Applications
System Control Unit - Digital Modules (SCU-DM)
7.14
Miscellaneous Control
This module consists of the Bit-Protection Scheme and general system control SFRs.
7.14.1
Bit Protection Register
The Bit-Protection Scheme disallows direct software writing of selected bits (i.e. Protected bits) by the SFR
PASSWD. When the bit field MODE is 11
B
, writing 10011
B
to the bit field PASS opens access to writing of all
protected bits and writing 10101
B
to the bit field PASS closes access to writing of all protected bits. Note that
access is opened for maximum 32 CCLKs if the “close access” password is not written. If “open access”
password is written again before the end of 32 CCLK cycles, there will be a recount of 32 CCLK cycles.
Note:
It is recommended to disable interrupts before writing to this register, otherwise interrupts might delay
the write access the protected bits in a way that the 32-cycles-access-window is closed already.
Password Register
SCU_PASSWD
Offset
Reset Value
Password Register
0AC
H
see
Field
Bits
Type
Description
RES
31:8
r
Reserved
Returns 0 if read; should be written with 0.
PASS
7:3
rw
Password Bits
The Bit-Protection Scheme only recognizes three
patterns.
This Bit field is always read as ‘0’.
11000
B
Enables writing of the bit field MODE.
10011
B
Opens access to writing of all protected bits.
10101
B
Closes access to writing of all protected bits.
PROTECT_S
2
r
Bit-Protection Signal Status Bit
This bit shows the status of the protection.
0
B
Software is able to write to all protected bits.
1
B
Software is unable to write to any protected bits.
31
16
r
RES
15
8
r
RES
7
3
rw
PASS
22
r
PROT
ECT*
1
0
rw
PW_MODE