Copy Microcontroller PIC16C57A Heximal out from its memory, and reprogramme the firmware to blank PIC16C57A for MCU cloning, the whole process needs to get access to the databus which among CPU and memory;

The Oscillator Calibration (OSCCAL) register is used to calibrate the internal 4 MHz oscillator. It contains four to six bits for calibration when read mcu at89c51cc03 program.

Increasing the cal value increases the frequency. See Section 7.2.5 for more information on the internal oscillator. As a program instruction is executed, the Program Counter (PC) will contain the address of the next program instruction to be executed.

The PC value is increased by one every instruction cycle, unless an instruction changes the PC. For a GOTO instruction, bits 8:0 of the PC are provided by the GOTO instruction word. The PC Latch (PCL) is mapped to PC<7:0> after extract Microcontroller at89c51ic2 program.

Bit 5 of the STATUS register provides page information to bit 9 of the PC For a CALL instruction, or any instruction where the PCL is the destination, bits 7:0 of the PC again are provided by the instruction word.

However, PC<8> does not come from the instruction word, but is always cleared. The Program Counter is set upon a RESET, which means that the PC addresses the last location in the last page i.e., the oscillator calibration instruction.

After executing MOVLW XX, the PC will roll over to location 00h, and begin executing user code. The STATUS register page preselect bits are cleared upon a RESET, which means that page 0 is preselected before extracting ic code.

Therefore, upon a RESET, a GOTO instruction will automatically cause the program to jump to page 0 until the value of the page bits is altered.