Техническая Спецификация для Freescale Semiconductor MC56F8006 Demo board MC56F8006DEMO MC56F8006DEMO

Freescale Semiconductor

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A user can un-secure a secured device by programming the word 0x0000 into program flash location 0x00 1FF7. After 
completing the programming, the JTAG TAP controller and the device must be reset to return to normal unsecured operation.

You are responsible for directing the device to invoke the flash programming subroutine to reprogram the word 0x0000 into 
program flash location 0x00 1FF7. This is done by, for example, toggling a specific pin or downloading a user-defined key 
through serial interfaces. 

Flash contents can be programmed only from 1s to 0s.

It is possible to temporarily bypass the security through a back door access scheme, using a 4-word key, to temporarily unlock 
of the flash. A back door access requires support from the embedded software. This software would typically permit an external 
user to enter a four word code through one of the communications interfaces and then use it to attempt the unlock sequence. If 
your input matches the four word code stored at location 0x00 1FFC–0x00 1FFF in the flash memory, the part immediately 
becomes unsecured (at runtime) and you can access internal memory via JTAG/EOnCE port. Refer to the MC56F8006 
Peripheral Reference Manual for detail. The key must be entered in four consecutive accesses to the flash, so this routine should 
be designed to run in RAM.

The recommended method of unsecuring a secured device for product analysis of field failures is via the method described in 

.” The customer would need to supply technical support 

with the details of the protocol to access the subroutines in flash memory. An alternative method for performing analysis on a 
secured device would be to mass-erase and reprogram the flash with the original code, but modify the security word or not 
program the security word.

The 56F8006/56F8002 is fabricated in high-density low power and low leakage CMOS with a maximum voltage of 3.6 V digital 
inputs during normal operation without causing damage. 

Absolute maximum ratings in 

 are stress ratings only, and functional operation at the maximum is not guaranteed. Stress 

beyond these ratings may affect device reliability or cause permanent damage to the device.

Unless otherwise stated, all specifications within this chapter apply over the temperature range of –40ºC to 105ºC ambient 
temperature over the following supply ranges: V

SS

= V

SSA

= 0V, V

DD

= V

DDA

= 3.0–3.6 V, CL < 50 pF, f

OP

= 32 MHz

This device contains protective circuitry to guard against damage due to high static voltage 
or electrical fields. However, normal precautions are advised to avoid application of any 
voltages higher than maximum-rated voltages to this high-impedance circuit. Reliability of 
operation is enhanced if unused inputs are tied to an appropriate voltage level.