The first step to remove Protected P89LPC938 Chip Firmware is located the security bits and disable it.
The Security Bit protects against software piracy and prevents the contents of the flash from being read by unauthorized parties in Parallel Programmer Mode which is quite common when Copy microcontroller. It also protects against code corruption resulting from accidental erasing and programming to the internal flash memory.
When the Security Bit is activated all parallel programming commands except for Chip-Erase are ignored (thus the device cannot be read). However, ISP reading, writing, or erasing of the user’s code can still be performed if the serial number and length has not been programmed.
Therefore, when a user requests to program the Security Bit, the programmer should prompt the user and program a serial number into the device after ST62T65 Chip Protected Memory has been broken. The device supports eight interrupt sources under a four level priority scheme.
Below Table summarizes the polling sequence of the supported interrupts.