C508_01 Datasheet, PDF (258/267 Pages) Infineon Technologies AG – 8-Bit CMOS Microcontroller

C508
OTP Memory Operation
The state of the lock bits can always be read if protection Level 0 is selected. If protection
Level 1 to 3 has been programmed and the programming mode has been left, it is not
possible to re-enter the programming mode. In this case, the lock bits can no longer be
read.
Figure 10-7 shows the waveform of a lock bit write/read access. For simplicity, the
PROG pulse is shortened. In reality, a 100 µs PROG low pulse must be applied for lock
bit programming.
PMSEL1,0
PALE
Port 0
(D1, D0)
PROG
PRD
1,0
1,0
1,0
MCT03365
The example shows the programming and reading of a protection level 1.
Figure 10-7 Write/Read Lock Bit Waveform
User’s Manual
10-12
2001-05