880
Chapter 28
On-Chip Debug Unit
Preliminary User’s Manual U17566EE1V2UM00
Security disable
The entire ID code, i.e. also the security bit 7 of address 0000 0079
H
, can be
made temporarily ineffective by software. This is achieved by setting the
control bit RSUDISC.DIS = 1. Setting RSUDISC.DIS = 1 does not change the
security bit. Thus after a Power-On-Clear reset the N-Wire security is effective
again.
The N-Wire security function can not be suspended when the microcontroller
is operating in N-Wire debug mode.
(1)
RSUDISC- N-Wire security disable control register
The 8-bit RSUDISC register is used to temporarily disable the N-Wire security
function.
Access
This register can be read/written in 8-bit or 1-bit units.
Writing to this register is protected by a special sequence of instructions.
Please refer to
“RSUDISCP - RSUDISC write protection register” on page 881
for details.
Address
FFFF F9E0
H
.
Initial Value
00
H
. This register is cleared by Power-On-Clear reset.
RSUDISC.DIS can not be changed, while the microcontroller is operating in
N-Wire debug mode, i.e. while the concerned ports are operating as N-Wire
debug pins (OCDM.OCDM0 = 1).
Thus proceed as follows to
• enable N-Wire debugging (from status OCDM.OCDM0 = 0):
– set RSUDISC.DIS = 1 (disable N-Wire security)
– set OCDM.OCDM0 = 1 (ports are N-Wire pins)
• disable N-Wire debugging (from status OCDM.OCDM0 = 1):
– set OCDM.OCDM0 = 0 (ports are not N-Wire pins)
– set RSUDISC.DIS = 0 (ensable N-Wire security)
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
DIS
R
R
R
R
R
R
R
R/W
Table 28-1
RSUDISC register contents
Bit position
Bit name
Function
0
DIS
N-Wire security function disable:
0: N-Wire security function enabled.
1: N-Wire security function disabled.
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