Memory
MCF51CN128 Reference Manual, Rev. 6
Freescale Semiconductor
4-33
Figure 4-10. Procedure for Clearing Security on MCF51CN128 Series MCUs via the BDM Port
secure state unknown / unpowered
secure state unknown, CPU halted, FEI 10MHz
clock, sync required
secure state unknown,, CPU halted, FEI 10MHz
clock, synchronized to debugger
hold BKGD=0, apply power, wait N+16 cycles for
POR to de-assert
SYNC
set PRDIV8 and clock divider fields in CSR3
write xcsr[31:24]=0x8F to transfer divider info to
FTSR
xcsr[31:24]==0x87
STOP
STOP
already unsecured
error condition
check code or device
N = number of cycles for SIM to release
internal reset. Adder of 16 imposed by the
ColdFire core.
BKGD=0 during reset will
ensure that ENBDM comes up "1"
FLL Enabled, Internal Reference (FEI)
at 10MHz is reset default for the ICS
Read XCSR
xcsr[31:24] != 1000 01-1
xcsr[25]=0
Write PTIMER bits to CSR3
write xcsr[31:24]=0x97 to transfer PTIMER info to
FTSR and initiate erase/verify of flash memory
A
secure state unknown / unpowered
secure state unknown, CPU halted, FEI 10MHz
clock, sync required
secure state unknown,, CPU halted, FEI 10MHz
clock, synchronized to debugger
hold BKGD=0, apply power, wait N+16 cycles for
POR to de-assert
SYNC
set PRDIV8 and clock divider fields in CSR3
write xcsr[31:24]=0x8F to transfer divider info to
FTSR
xcsr[31:24]==0x87
STOP
STOP
already unsecured
error condition
check code or device
N = number of cycles for SIM to release
internal reset. Adder of 16 imposed by the
ColdFire core.
BKGD=0 during reset will
ensure that ENBDM comes up "1"
FLL Enabled, Internal Reference (FEI)
at 10MHz is reset default for the ICS
Read XCSR
xcsr[31:24] != 1000 01-1
xcsr[25]=0
Write PTIMER bits to CSR3
write xcsr[31:24]=0x97 to transfer PTIMER info to
FTSR and initiate erase/verify of flash memory
A