Fujitsu FR81S User Manual
CHAPTER 47: ON CHIP DEBUGER (OCD)
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: ON CHIP DEBUGGER : OCD
FUJITSU SEMICONDUCTOR CONFIDENTIAL
24
5.2.2. Security Function
Security function is shown.
OCDU has the security function. OCDU enables the security function by setting the security information
stored in a debug security area of the memory space in CPU. If the security function is enabled, OCDU enters
the security lock state. To release this, the security is unlocked by writing a password set in the security
information to the number of specified length and the E_SLPR register.
Security Information
The debug security area is allocated at 30 bytes of built-in flash start address+4 to +33. For OCDU, see this
area using the security sequence.
The following security information is available for the debug security area.
Security password length (PW length)
The security password length is 16-bit data in the start address of the debug security area, and the lower 4 bits
are the enabled PW length. The upper 12 bits have no effect on operation. If the PW length is 0x0 or 0xF, the
security is disabled. If the PW length is 0x1 to 0xE (1 to 14), the security is enabled.
Security password (PW)
The security password is 16-bit data in the debug security area. 14 areas that writes data are provided. The PW
is assigned from an address next to the PW length address, in the order of PW1, PW2,... PW14 (See figure
below). If the security is enabled (PW length:1 to 14), the value of the PW length indicates the enabled PW.
(Example : If the PW length is 8, PW1 to PW8 are enabled, and PW9 to PW14 are disabled.)
Address
15
0
ROM/Flash start address +4
PW length
ROM/Flash start address +6
PW1
ROM/Flash start address +8
PW2
∙∙∙
∙∙∙
ROM/Flash start address +32
PW14
Note:
If the security function of the on chip debugger (OCD) is not used, nothing is written to this area and the initial
state (all bits=1) immediately after flash erase is retained.
MB91520 Series
MN705-00010-1v0-E
2035