We can Reading Microprocessor PIC16C642 binary, please view the Microprocessor PIC16C642 features for your reference:
Once Synchronous mode is selected, reception is enabled by setting either enable bit, SREN (RCSTA<5>), or enable bit, CREN (RCSTA<4>). Data is sampled on the RC7/RX/DT/SDI/SDA/SEG8 pin on the falling edge of the clock. If enable bit SREN is set, then only a single word is received when reading the microprocessor binary.
If enable bit CREN is set, the reception is continuous until CREN is cleared. If both bits are set, CREN takes precedence. After clocking the last bit, the received data in the Receive Shift Register (RSR) is transferred to the RCREG register (if it is empty) if binary from microprocessor being read.
When the transfer is complete, interrupt flag bit, RCIF (PIR1<5>), is set. The actual interrupt can be enabled/disabled by setting/clearing enable bit, RCIE (PIE1<5>). Flag bit RCIF is a read-only bit which is reset by the hardware before read the microprocessor binary.
In this case, it is reset when the RCREG register has been read and is empty. The RCREG is a double-buffered register (i.e., it is a two-deep FIFO). It is possible for two bytes of data to be received and transferred to the RCREG FIFO and a third byte to begin shifting into the RSR register after microprocessor bin being read.
On the clocking of the last bit of the third byte, if the RCREG register is still full, then Overrun Error bit, OERR (RCSTA<1>), is set. The word in the RSR will be lost. The RCREG register can be read twice to retrieve the two bytes in the FIFO of reading microprocessor bin.
Bit OERR has to be cleared in software (by clearing bit CREN). If bit OERR is set, transfers from the RSR to the RCREG are inhibited so it is essential to clear bit OERR if it is set. The ninth receive bit is buffered the same way as the receive data. Reading the RCREG register will load bit RX9D with a new value, therefore, it is essential for the user to read the RCSTA register before reading RCREG in order not to lose the old RX9D information when read MCU.
